: So how many people have had overheating/bad head gasket problems?



JAvery20
03-06-04, 04:02 AM
It seems like this is an epidemic. Somewhat high mileage Northstars.. over heating due to bad head gaskets. Especially 93-95 years. Im just wondering how many people on the forum have had this problem. Ive run into quite a few around town and have read about quite a few on the various forums.

Im actually picking my car up tomorrow from its head gasket repair. :rolleyes2 Its a 93 ETC btw.

fristim
03-06-04, 04:38 AM
It seems like this is an epidemic. Somewhat high mileage Northstars.. over heating due to bad head gaskets. Especially 93-95 years. Im just wondering how many people on the forum have had this problem. Ive run into quite a few around town and have read about quite a few on the various forums.

Im actually picking my car up tomorrow from its head gasket repair. :rolleyes2 Its a 93 ETC btw.


I myself haven't had any head gasket problems but then agian I have a 98 concours. My question is how much did your fix cost you and who did you have do it?

JAvery20
03-06-04, 05:00 AM
well I took it to a few guys around town and they all told me it would be cheaper to just drop a new engine in. well that equates to i just dont wanna do headgaskets or im scared of that cadillac emblem. :p So i was looking at about 3 grand for a new engine or a new head gasket. :bonkers: Ive heard ppl quoted on the forums saying expect anywhere from 2500-4000 for my particlular problem. :hmm: :bonkers:

I thought that was a little crazy, since the engine only had 120k on it and ran like a champ. I was either going to run it into the ground or find somebody that would not screw me over and just do the head gasket. I eventually found somebody that quoted me 700 up front. He knew my dad and said he just did a head gasket on a northstar cadillac a week ago. So i was happy, and hopefully everything works out when i pick her up tomorrow.

capn
03-06-04, 06:44 PM
ive got a 94 ETC and the only overheating problem ive had is due to a hole in the radiator but other than that it stays about 196 degree and is a strong engine

Anthony Cipriano
03-06-04, 11:05 PM
It seems like this is an epidemic. Somewhat high mileage Northstars.. over heating due to bad head gaskets. Especially 93-95 years. Im just wondering how many people on the forum have had this problem. Ive run into quite a few around town and have read about quite a few on the various forums.

Im actually picking my car up tomorrow from its head gasket repair. :rolleyes2 Its a 93 ETC btw.

A couple of points. There are millions of Northstar engines on the road. Overall, very few of them have head gasket or overheating problems. Reading this forum will lead you to the conclusion that all Northstars blow head gaskets, use oil, leak oil, etcetera. That's the nature of internet forum. Read a Mercedes forum and you would think that their cars are junk. Same with Lexus. They "all" broke timing belts on that site. There's a BMW 750i hate site. "All" of those overheat, needed new blocks, etcetera. Get the idea? No one looks up or searches out a forum to brag about how good their car is. But everyone with a problem looks up the appropriate site to vent, bitch, commiserate, complain, etcetera. So all internet sites make the specific brand look like there is an epidemic of problems.

There are quite a few 93, 94, 95 Northstars showing up with failed head gaskets the last few years. There is a reason. It's called lack of maintenance. The Northstar is an all aluminum engine. Any and every all alluminum engine is very susceptible to internal damage due to corrosion if the cooling system isn't maintained. The 93, 94, 95 Northstars, specifically, were factory filled with the conventional green, silicated coolant that specifically required replacement every 2-3 years/24-32,000 miles to keep the corrosion inhibitors in the coolant at the correct strength. If the coolant is left in the sytem too long the corrosion inhibitors become depleted (even though the coolant looks nice and green and "checks" good for temperature protection) and the engine and cooling system can corrode internally. This leads to failed head gaskets as the steel core of the laminated head gaskets will start to corrode from the edges at the coolant jackets and eventually just rot away from the inside out. Purely an issue of lack of maintenance by the previous owners.

The Northstar is very easy to repair in this case as even stripped head bolt holes can be easily repaired with the correct Timesert thread repair inserts. It just takes a knowlegable mechanic with the proper tools and instruction. A factory shop manual is absolutely mandatory doing repairs to the engine as it does require special assembly and bolt tensioning techniques.

becker_jr
03-07-04, 04:47 PM
I have '98 model SLS with 55,000 miles.
Over the past half year I noticed that the coolant needed to be refilled several times with about a liter every time. The workshop could not find any fault.
Then in the beginning of February the heating suddenly disappeared an a few minutes later the engine temperature started to rise and fluctuate above the normal temperature to quickly travel close to the red. I stopped the car and the engine. A few minutes later, I started the engine again. Now the engine temperature quickly returned to almost normal. I drove to my garage after again having refilled the coolant, but now about a gallon. The garage again could not find anything wrong, not even after a 20-minute drive on the highway. No coolant was missing.
I now drove home, but after 5 miles, the same behavior returned, with fluctuating indicator needle, heat disappeared. When getting home I checked the coolant, which again was low by about a gallon. I refilled and returned to the garage. This time they did find exhaust gases in the coolant.
They believed it to be the head gasket(s).

Removing the entire engine and transaxle assembly to get to the head gasket, it was discovered that one of the gaskets was half way perforated at one of the cylinders, but the metal sealant around the actual cylinder looked ok. The head-bolts were all tightly pulled.

The conclusion was that the head gasket must have been bad quality, perhaps leaking for some long time. The care has not been driven hard.

The entire procedure cost $5000 to get fixed, including replacement parts and coolant. This car has been meticulously taken care of. No scheduled maintenance skipped and all fluid levels regularly checked.

Lack of maintenance was not the reason, but poor head gasket quality.

Lawrence
03-07-04, 04:58 PM
I'll have to agree. My 94 STS is down right right now for head gaskets. There is no (0) corrosion to the head gaskets or to any other part of the cooling system. The motor has 73K miles.

On this motor the head bolts pulled right out of the block.

Whether the car was over heated or not I don't know as I haven't owned it since new, but an overheat still should not cause the headbolts to pull out. It could cause the head gasket to compress enough to cause it to "collapse" from under the head. But still wouldn't explain the pulled/stripped head bolts.

I beleive the problem to be the integrity of the block threads. Which, with out any manufacturing changes, or time-serts, could have been to a great extent prevented with studs for mounting the heads. Studs do not distress the block threads upon installation, thus retaining 100% of the integrity originally designed, and more. Simply put, they are much stonger.

This being my impression of this particular engine. This is the only one I have diassembled. It is entirely possible I have a defective one. But IF the same failures are typical to the NS' s I would say they have a problem.

becker_jr
03-08-04, 10:05 AM
On the bolt problem, that Lawrence is writing about.
I have heard from the workshop that the bolts today are of a kind, which are tightened not with specific torque, but instead a specific angle. These bolts are called tension-bolts. You get the intended force to hold down the top through the head gasket to the engine block through, as it were, a spring, although with restricted elasticity. Sometimes these bolts snap, usually were the thread is. In order to remove these, GM is said to have developed a special tool enabling the removal of that part without having to take off the top. That is supposing that the head gasket is not leaking.
It seems that broken tension bolts is not that uncommon as witnessed here (http://www.rotaryaviation.com/Squawk_Tension_bolts.htm).
A search for ďtension boltĒ using Google returns 1690 hits.

My car did not have that problem though.

Realtor1
03-08-04, 01:11 PM
A couple of points. There are millions of Northstar engines on the road. Overall, very few of them have head gasket or overheating problems. Reading this forum will lead you to the conclusion that all Northstars blow head gaskets, use oil, leak oil, etcetera. That's the nature of internet forum. Read a Mercedes forum and you would think that their cars are junk. Same with Lexus. They "all" broke timing belts on that site. There's a BMW 750i hate site. "All" of those overheat, needed new blocks, etcetera. Get the idea? No one looks up or searches out a forum to brag about how good their car is. But everyone with a problem looks up the appropriate site to vent, bitch, commiserate, complain, etcetera. So all internet sites make the specific brand look like there is an epidemic of problems.

There are quite a few 93, 94, 95 Northstars showing up with failed head gaskets the last few years. There is a reason. It's called lack of maintenance. The Northstar is an all aluminum engine. Any and every all alluminum engine is very susceptible to internal damage due to corrosion if the cooling system isn't maintained. The 93, 94, 95 Northstars, specifically, were factory filled with the conventional green, silicated coolant that specifically required replacement every 2-3 years/24-32,000 miles to keep the corrosion inhibitors in the coolant at the correct strength. If the coolant is left in the sytem too long the corrosion inhibitors become depleted (even though the coolant looks nice and green and "checks" good for temperature protection) and the engine and cooling system can corrode internally. This leads to failed head gaskets as the steel core of the laminated head gaskets will start to corrode from the edges at the coolant jackets and eventually just rot away from the inside out. Purely an issue of lack of maintenance by the previous owners.

The Northstar is very easy to repair in this case as even stripped head bolt holes can be easily repaired with the correct Timesert thread repair inserts. It just takes a knowlegable mechanic with the proper tools and instruction. A factory shop manual is absolutely mandatory doing repairs to the engine as it does require special assembly and bolt tensioning techniques.

Well said Anthony and I totally agree....unfortunatly now is the time people with the 93-95 engines will pay the price for lack of maintenace on these cars.

Lawrence
03-08-04, 02:30 PM
Well said Anthony and I totally agree....unfortunatly now is the time people with the 93-95 engines will pay the price for lack of maintenace on these cars.

Don't get me wrong, I agree with the maintanence issue. That's holds true with anything. But you can't answer every problem with that.

All I'm saying is that was not the cause of my failure. The motor was replaced 03/97 (new coolant) and was down again for a coolant hose again in 99. That was the first owner. The next owner had serviced the cooloing system at least once. And that was one of the first things I did as well. the motor now has 73k on it. The right now the motor is down and there is no corrosion in this system, with the possible exception of the block threads for the head bolts.

A deteriorated head gasket, no matter the cause, should not cause the head bolts to pull. In my motor the head bolt issue caused the head gasket failure, not the other way around. The head gasket it self looks as good as the new one. It's tough to prove without some extenstive tests (that I don't have the eqipment to do), but I beleive the block threads were damaged before they were removed (and again, they should still be removable). I would assume from the thermocyling, with a possible contributing factor being stress at installation. Both issues being a design considerations.

I am not a professional engineer or even mechanic, but I've had enough engines apart to know a design weakness is when I see it. I've also owned many cars, as well as those of friends and family, and have never seen such a thing. IMHO this is not a normal failure. How many head bolt kits do you see from Time-Sert for any other engine?

Thats my story and I'm stikin' to it.

ljklaiber
03-08-04, 03:20 PM
No opinion here, just what I ride and what i maintain.

95 sls 141k puchased with 122k. Coolant was a clear type that checked for temp ratings. I carefully cleaned and degreased the radiator fins with a good shop spray cleaner and mild hose pressure in both directions. I burn 93 Amoco exclusively, with 1 oz Redline S1-1 fuel conditioner per fill up.

Oil is changed per 2500 miles with AC FIlter...(Valvoline Max life 10-30.)

Battery is DieHard Gold..100 month and fluid kept up. .. Best I could get type.
I change paper filter when I change oil, as I do with all vehicles for best performance.

Added 4oz of Bars Leak once.

Just did three short trips on Interstes here in SC and Georgia. 80 in traffic...201 Degrees max. (90 -95 into the wind goin to Macon 205)

100+ in short bursts alone and comin home 203.

It may blow tomorrow, but so far this is a fine ride.

I spend more time on cold start warm up, as it is an all alloy engine with a different expansion need than Castion.


Hope this helps. ljk :coolgleam

ljklaiber
03-08-04, 03:24 PM
No opinion here, just what I ride and what i maintain.

95 sls 141k puchased with 122k. Coolant was a clear type that checked for temp ratings. I carefully cleaned and degreased the radiator fins with a good shop spray cleaner and mild hose pressure in both directions. I burn 93 Amoco exclusively, with 1 oz Redline S1-1 fuel conditioner per fill up.

Oil is changed per 2500 miles with AC FIlter...(Valvoline Max life 10-30.)

Battery is DieHard Gold..100 month and fluid kept up. .. Best I could get type.
I change paper filter when I change oil, as I do with all vehicles for best performance.

Added 4oz of Bars Leak once.

Just did three short trips on Interstes here in SC and Georgia. 80 in traffic...201 Degrees max. (90 -95 into the wind goin to Macon 205)

100+ in short bursts alone and comin home 203.

It may blow tomorrow, but so far this is a fine ride.

I spend more time on cold start warm up, as it is an all alloy engine with a different expansion need than Castion.


Hope this helps. ljk :coolgleamPaper filter above was meant to say AIR Filter, Castion means Cast Iron. Sorry bout my typing...lol

Anthony Cipriano
03-08-04, 03:43 PM
How many head bolt kits do you see from Time-Sert for any other engine?

Most every aluminum engine has some sort of thread repair process. Stripping threads in aluminum parts is pretty common in service as the threads are obviously not a strong as cast iron and they can be easily damaged through galling and debris and cross threading and such.

The timesert kit was developed as a normal development process for designing the necessary service tools before the engine ever went into production. It was not something that was done in response to head bolt problems. It was done as normal due care to provide the necessary tools to repair the engine in the field.

Stripped threads are not something that's necessarily expected or anticipated when designing an aluminum engine but understanding aluminum it's obvious that threads can be damaged and that repairs will be necessary. In aluminum and with highly loaded joints like the head bolts there are a lot of thread repairs that wont work (like heli-coils in specific) so the service kit was developed and validated with time to make positively sure the correct tools and materials were in the field for successful service.

It's hard to say without seeing the parts what happened to the head bolts in your engine. It is pretty rare for "all" the head bolts to just pull out like described. The failures of head bolts usually happen at assembly when the threads are not cleaned or the tech cleans the threads with a cutting tap (quickest way to ruin the threads) or something like that. Occasionally a thread will fail when being tensioned due to some porosity in the casting in that area weakening the threads but for them to just "pull out" is something that's hard to understand.

There was a great deal of sealing and fastening work done on the head bolt joint on the Northstar. The fact that it's under a lot of load and stress and that aluminum expands more than steel was not "missed" by the engineers involved.

Anthony Cipriano
03-08-04, 04:01 PM
On the bolt problem, that Lawrence is writing about.
I have heard from the workshop that the bolts today are of a kind, which are tightened not with specific torque, but instead a specific angle. These bolts are called tension-bolts. You get the intended force to hold down the top through the head gasket to the engine block through, as it were, a spring, although with restricted elasticity. Sometimes these bolts snap, usually were the thread is. In order to remove these, GM is said to have developed a special tool enabling the removal of that part without having to take off the top. That is supposing that the head gasket is not leaking.
It seems that broken tension bolts is not that uncommon as witnessed here (http://www.rotaryaviation.com/Squawk_Tension_bolts.htm).
A search for ďtension boltĒ using Google returns 1690 hits.

My car did not have that problem though.

Good observation. But there's nothing specifically different about the bolts in the way they work. "Tension bolts"? All bolts are tension bolts. That's how bolts work! There's nothing unique in the Northstar head bolts in this area.

Every bolt is considered a "spring" as described. The bolt is installed and tightened. As the bolt is tightened it's stretched to tension it - to impart a spring load or "clamp load" on the joint. A sealing and fastening engineer will design the joint and the gasket to require a certain clamp load to seal, and, based on the load of the parts in operation, the clamp load must have exceded that working stress to hold the joint together. The bolt is simply a long spring. If you put a bolt in a machine and stretch it you will see a spring rate for that bolt. Bolts are generally very stiff so they don't stretch much - and as they stretch that little bit the force required to stretch them goes up astromonically. But it's at a rate none-the-less. So, if the load required to seal the joint is a certain amount and the spring rate of the bolt is known then it can quickly be determined how far the bolt will have to be stretched to get that load. Once again, nothing unusual here, all bolts work this way.

The thing that's unique in a way about the bolts in the Northstar is the means used to tension or stretch them. Torqueing a bolt is a misnomer in a way because it's an indirect measurement of the amount of stretch in the bolt. It would be much more desireable and accurate to measure the stretch of the bolt directly. This is often done with critical fasteners like rod bolts where the bolt is open at both ends. ARP commonly gives the specs to tension the high performanced rod bolts in terms of the amount of stretch to be measured with a micrometer. Just turn the bolt until it stretches a certain amount. With head bolts this can't be done as the hole is blind. To get the similar accuracy the spec is given as a torque and angle - such as 80 nm plus 180 degrees. The torque is speced to just get the joint to zero clearance - pull all the slack out of it. And the angle is based on the thread pitch. Turn the bolt that many degrees and the tread pitch will stretch it that much ie. if the bolt has a 1mm per turn pitch and you want to stretch it 0.5 mm to get the necessary load then the "angle" would be 180 degrees. Half of a turn or half of the 1mm thread pitch. Simple as that. All bolts can be tensioned this way - not just the Northstar bolts.

Torqueing a bolt is a notoriously inaccurate way to tension it. The "torque" being applied is used up in friction in the threads, friction under the head of the bolt and to stretch the bolt. If the friction changes even a little it affects the amount of torque used to stretch the bolt (and tension it) dramatically. So, the torque-angle method is used to minimize this. The "torque" given is very low. Just enough to zero the joint and not create a lot of friction in the threads or under the head. Then the "angle" spec actually stretches the bolt accurately based on the geometry of the threads. This also helps to eliminate inaccuracies from oil and grease on the threads and such as the "angle" ignores this. Plus, if a bolt bottoms out in a hole then it will be self policing as it'll be impossible to turn the bolt to the prescribed angle - as it'll stop when it bottoms. If torque alone is used, a bottomed bolt will check "tight" even though it is not clamping the joint.

There are some bolts used in engines called "torque to yield" where the bolt is actually designed to deform as it's tightened. A torque to yield bolt can only be used once as every time it's used it gets longer and longer and eventually will snap in two. The Northstar head bolts are not torque to yield fasteners. They're specified for one use only as they are highly loaded and require the proper anti-lock coatings applied to them. The blue thread coating and the red coating on the washer act as installation high pressure lubricants and then thread locking agents so the head bolts don't loosen. Aluminum engines like to loosen the head bolts if they aren't locked in place. Ask Honda about that...

Anthony Cipriano
03-08-04, 04:10 PM
Coolant was a clear type that checked for temp ratings.


Added 4oz of Bars Leak once.



I spend more time on cold start warm up, as it is an all alloy engine with a different expansion need than Castion.

:coolgleam

A couple of observtions. The reason that the coolant must be drained and replaced is that it has corrosion inhibitors in it that deplete over time. That can't be measured. Even though the coolant might check fine for temperature protection it must be drained and replaced occasionally. The coolant is mostly ethylene-glycol - that's what provides the freezing and boiling protection. The EG is usually fine and could last forever. The corrosion ihibitors, however, don't last forever, particularily with the green conventional silicated coolant.

The green stuff used prior to 1996 must be replaced every 2-3 years/24-32,000 miles. The orange DexCool (that your car should have come with) will last 5 years /100,000 miles although replacing it more often doesn't hurt. There is no approved coolant that's "clear". I would drain the system as completely as possible and refill with fresh 50/50 DexCool/distilled water for the most protection of the cooling system.

The system is factory filled with the coolant supplement/sealer and that should be used at each drain/refill to avoid nuisance leaks. Aluminum castings will exhibit a certain level of porosity over time so the sealer is used to prevent leaks. Personally, I recommend 6 of the GM coolant supplement pellets or two tubes of the BarsLeaks "golden seal" to seal the system in a Northstar. The sealer must be installed in one of the radiator hoses and not the surge tank. There's little active flow through the surge tank so the sealer cannot disperse through the system.

Anthony Cipriano
03-08-04, 04:18 PM
The corrosion of the head gasket mentioned cannot be observed by simply looking at the head gasket. It's not going to turn red with rust. What happens is the central core of the head gasket, which is a spring steel for resiliancy, comes into contact with the coolant at the coolant ports in the head gasket. If the corrosion inhibitors are depleted in the coolant the central core or steel substraight of the head gasket starts to corrode and lose it's strength. Without the core intact the head gasket loses it resiliency and collapses. It'll still look fine on the surface oftentimes. Usually, if you scrape away the compacted graphite surface of the gasket in the area of the coolant transfers you can find the blackened, corroded steel core.

The thermal expansion of the engine during warmup was well understood by the designers. There is really no need to do any sort of specific warmup or anything to the Northstar. That's one reason it has such a high flow water pump with a very high bypass ratio. During warmup there's a great deal of coolant being flushed through the engine to maintain a constant temperature and eliminate any thermal gradients during warmup. Even though the thermostat is closed the coolant is circulating very rapidly through the engine to keep the thermal gradients low - so the whole engine warms up uniformly. The internal recirculation rate actually goes way down once the termostat opens and allows radiaotor flow for cooling. The rapid internal recirculation is necessary to prevent any damage during warmup due to thermal expansion differences and the large thermal growth of aluminum. It has proven to be very effective at controlling the thermal gradients as the Northstar does very well on head gasket extreme tests run with high thermal cycling rates specifically designed to "kill" head gaskets.

Lawrence
03-08-04, 04:29 PM
It's pretty rare for "all" the head bolts to just pull out like described. The failures of head bolts usually happen at assembly when the threads aren't cleaned or the tech cleans the threads with a cutting tap (quickest way to ruin the threads) or something like that. Occasionally a thread will fail when being tensioned due to some porosity in the casting in that area weakening the threads but for them to just "pull out" is something that's hard to understand.

Yep, that's about the way I feel about it. But these things did indeed pull. As I said in another post, all the ones I noticed (at least the bad ones) were on the rear head and it was at least 8 of the 10. The threads came out on the bolts. I had a hard time with the Time-Sert process because there wasn't enough thread there to hold the guide plate down finger tight. Strangely, the front head seemed OK, with threads coming out with the bolts on only, maybe two bolts. And only a couple of threads. On the rear most of the threads came with the bolt. I am sure this motor was a factory sealed, never apart, motor so there are no repair errors or miscue's.


There was a great deal of sealing and fastening work done on the head bolt joint on the Northstar. The fact that it's under a lot of load and stress and that aluminum expands more than steel was not "missed" by the engineers involved.

I have seen a lot of aluminum block/head motors that don't have any problems like this. Granted, sometimes after several RR's they may have a couple let go, as you said upon reassembly, and that's to be expected. Usually studs prevent this. The engineers may not have "missed" consideration of this area but I would say they have, at least judging by this motor, under estimated the forces at work here (assuming there is no manufacturing defect). I couldn't pin point exactly what's happened here, but I do feel there is a problem. What happened judging by one damaged motor would probably be impossible.

Again, I have no experience with other NS motors, so it could be mine is the only one that has this problem. Some peculiar defect of material or workmanship. Maybe the guy on the line was hung over the day mine was made and used a bad tap or something on his side of the motor. And every other one you hear about failing is indeed from corrosion. Stranger things have happened. And Cadillac couldn't be faulted by that. But when you read of all the problems others are having with them, it starts to ring a bell. And you just have to answer. :)

Anthony Cipriano
03-08-04, 04:40 PM
In a way the Northstar is being it's own worst enemy. It's proving to last so well and run so good at even 100,000 miles and beyond that people are expecting it to be totally bulletproof. I think it's very reliable and robust but the fact is that the engines in the field are getting alot of miles on them. They're routinely going well over 100,000 and many 200,000 miles and even some at 300,000. And the cylinder walls are perfect, they don't wear out cams, etcetera.. Most engines in past history didn't have such a good track record of all the engines going 100,000 or further. They would have enough niggling and varied problems that they needed major service before 100,000. Northstars seem to run and run and eventually something will fail. It seems to be that the head gasket is the weaker link in many cases. I don't know if this is an idication of a bad head gasket design or not, Just that the head gasket is taking a lot of stress and wear and tear and that on any given engine it's one of the first things to start to give up.

Really, in perspective, the engine lasts pretty long and the cars hold together so well and don't rust that people are operating them at very high miles. Much further than cars in the past and the engines stay together pretty good. Even on engines that need a head gasket the rings, pistons and cylinder walls look perfect. Imagine your autoshop teacher 30 years ago showing you the "ridge" on the top of the cylinder wall from wear and then looking at a 250,000 mile Northstar that still has the original honing marks in the bore. Engines at 150,000 get a head gasket and the heads, valves, seats and guides are fine. Imagine that 30 years ago. Heads were due to knurling the guides and cutting the seats at 75,000. Lots of good things about the engine. The head gasket in general might be the "weak link" over the long haul but the weak link still goes a long way.

Lawrence
03-08-04, 05:23 PM
I agree, all pickin' and no praise. The engine is just a marvel to look at. I was really impressed with the enginering. So much in so little a package. Very simple in design, function and assembly. Just plain "smart" in every way. I love the motor. Hell, it could be an Indy 500 motor, at least 10 yrs ago. Only one thing I'd have changed, I'd have gone with free standing bores (I think the room could have been made up in the timing chain area). Of course that's picking again. They do go 300K right. In theroy I just like the free standing bore. Only other thing I could complain about, again based only on mine, is the casting porosity. I read somewhere GM pioneered the lost foam process. Well it was my understandind Mercury Marine did. Merc does have these engines going back many years. None the less, GM could take a lesson or two from Merc in that area. Merc has the nicest castings I have ever seen. Again I am splitting hairs. The NorthStar is a beautifull peice of work. I am equally impressed with the engine management system. But personally, I really appreciate the hard stuff.

I agree also about the life span. Yes, I remember well when a car was all done at 100K, and worthless. In fact just a few years ago a bank still wouldn't touch one. But, yes, I have come to expect much more of them today. You have to with the cost of them being what it is today. I fully expect a car, today, to go at least 200K with no major failures and I hope for 300K. I am satisfied with anything over 200K. Every car I have had for many years has done just that, with exception of one trans in my suburban that was probably my fault. And have never driven one that had any mechanical problems. All ran as good the day I got them rid if them as the day I bought them. No oil usage or anything like that. I never have gotten rid of a car because it wore out mechanically, only it gets too sore on the eyes.

So yes, give the NorthStar it due. It is a terrific engine and I am very proud it has a GM gadge on it.

Gomeo001
03-19-04, 04:24 PM
My 97 Deville d'Elegance heads are blown from overheating.

Anthony Cipriano
03-20-04, 01:05 AM
My 97 Deville d'Elegance heads are blown from overheating.

Is this the car that you have been posting about that was in an accident and sat for 8 months and now reportedly has "cracked heads"? Get your story straight. When did it overheat? Before or after the accident you mentioned? In one version the car was perfect before the accident and then the engine mysteriously got noisy after sitting for 8 months and needed "pistons" and then the heads were cracked and now you say it's head gaskets from overheating.

RLLOVETT
03-20-04, 06:45 PM
Now I, too, am a member of the Gasket Club (94 Eldo/128k)...Last Sunday I drove 20 minutes at about 70, then putted around town picking up 3 riders for a church social including a 300 pounder, and on the last 200 yards (up the hill to the church), the car noticeably lost power, the Stop Engine light came on and I made it to the parking lot in limp-home mode.
I let the car cool down, topped off with about 3/4 gal of 50/50 mix, and drove everybody home 3 hours later, watching the temp gauge. It ran about 203 instead of the usual 199, but no probs.
I took it to my gas-pumping mechanic on Fri for a routine LOF, told him the story and asked him to check the water pump tensioner, etc. He called me back to say hydrocarbons in the coolant--you need head gaskets, we're not changing the oil cuz you're gonna drain it anyway and we'll top off the coolant for free...
My local salvage yard owner has given me a good, cheap referral in the past for some frame work I needed done on another car, so I called him to see if he knew of anyone willing to work on N*. The guy he recommended is putting together a quote on an engine transplant because said it wasn't worth doing the gaskets, just get a new motor...The Frost Caddy dealer service guy on the phone said 1500-3000 for gaskets, depending.
I like this car--I (over) paid 6k for it last July (121k), and have about another 2k in rear brakes and new exhaust; most of the toys work, seats are ok, body clean. Should I throw Bars Leaks in it (and oil) and trade it? If I spend 3k with the dealer on gaskets, will I be entering the black hole of car ownership, where good money follows bad? Any advice on any of these issues would be helpful...thanks in advance!

dloch
03-20-04, 08:36 PM
I have a Northstar on my engine stand right now to do a swap with the one in my car with a leaking head gasket.

I'm in agreement with both anthony and lawrence. This motor is a thing of beauty inside.. Bill you guys really did your home work on this one. The rods look like the high price carillo pieces we use in our race engines. Although the reciprocating mass of the engines we run is much higher than the Northstar, I can easily see why this motor loves to wind.... and will do it all day long if you have the b@##'S to do it.

I will start a new thread with torque converter stall questions.

Anthony Cipriano
03-21-04, 12:15 AM
Now I, too, am a member of the Gasket Club (94 Eldo/128k)...Last Sunday I drove 20 minutes at about 70, then putted around town picking up 3 riders for a church social including a 300 pounder, and on the last 200 yards (up the hill to the church), the car noticeably lost power, the Stop Engine light came on and I made it to the parking lot in limp-home mode.
I let the car cool down, topped off with about 3/4 gal of 50/50 mix, and drove everybody home 3 hours later, watching the temp gauge. It ran about 203 instead of the usual 199, but no probs.
I took it to my gas-pumping mechanic on Fri for a routine LOF, told him the story and asked him to check the water pump tensioner, etc. He called me back to say hydrocarbons in the coolant--you need head gaskets, we're not changing the oil cuz you're gonna drain it anyway and we'll top off the coolant for free...
My local salvage yard owner has given me a good, cheap referral in the past for some frame work I needed done on another car, so I called him to see if he knew of anyone willing to work on N*. The guy he recommended is putting together a quote on an engine transplant because said it wasn't worth doing the gaskets, just get a new motor...The Frost Caddy dealer service guy on the phone said 1500-3000 for gaskets, depending.
I like this car--I (over) paid 6k for it last July (121k), and have about another 2k in rear brakes and new exhaust; most of the toys work, seats are ok, body clean. Should I throw Bars Leaks in it (and oil) and trade it? If I spend 3k with the dealer on gaskets, will I be entering the black hole of car ownership, where good money follows bad? Any advice on any of these issues would be helpful...thanks in advance!


Advice? Get another opinion. The "HC in the coolant test" isn't very reliable nor difinitive. There are several posts in the archives describing how to pressure check the combustion chambers for head gasket integrity. That's the only sure way of telling.

Make sure the system is full of fresh coolant of the correct 50/50 concentration and that the GM coolant supplement/Barsleaks "golden seal" is installed into the radiator hose - not the surge tank - and drive the car.

I just communicated with an owner several weeks ago with virutally your same exact circumstances. After much anguish over being told he had failed head gaskets he checked the coolant concentration and discovered that the coolant was good for freezing only to 20 degrees - not the -40 degrees that a 50/50 mix would provide. He drained the system and refreshed with the correct strength coolant and hasn't had a problem since.

Every time an engine overheats for any reason the immediate blame is placed on the head gaskets with little or no diagnosis. Make sure what the problem is before panicing. Most of the time it's not the head gaskets.

Things like the water pump drive belt, water pump drive belt tensioner, coolant concentration, thermostat, vapor vent line plugging, etcetera can all cause an overheat. Check the system and do a proper diagnosis before jumping to conclusions.

Anthony Cipriano
03-21-04, 12:22 AM
Now I, too, am a member of the Gasket Club (94 Eldo/128k)...Last Sunday I drove 20 minutes at about 70, then putted around town picking up 3 riders for a church social including a 300 pounder, and on the last 200 yards (up the hill to the church), the car noticeably lost power, the Stop Engine light came on and I made it to the parking lot in limp-home mode.
I let the car cool down, topped off with about 3/4 gal of 50/50 mix, and drove everybody home 3 hours later, watching the temp gauge. It ran about 203 instead of the usual 199, but no probs.
I took it to my gas-pumping mechanic on Fri for a routine LOF, told him the story and asked him to check the water pump tensioner, etc. He called me back to say hydrocarbons in the coolant--you need head gaskets, we're not changing the oil cuz you're gonna drain it anyway and we'll top off the coolant for free...
My local salvage yard owner has given me a good, cheap referral in the past for some frame work I needed done on another car, so I called him to see if he knew of anyone willing to work on N*. The guy he recommended is putting together a quote on an engine transplant because said it wasn't worth doing the gaskets, just get a new motor...The Frost Caddy dealer service guy on the phone said 1500-3000 for gaskets, depending.
I like this car--I (over) paid 6k for it last July (121k), and have about another 2k in rear brakes and new exhaust; most of the toys work, seats are ok, body clean. Should I throw Bars Leaks in it (and oil) and trade it? If I spend 3k with the dealer on gaskets, will I be entering the black hole of car ownership, where good money follows bad? Any advice on any of these issues would be helpful...thanks in advance!


You're getting poor advice from your junk yard about the desireability of replacing the head gaskets (if that really is the problem) vs. installing a used engine. But what would you expect from the junk yard? They want to sell you an engine. There's nothing in it for them if you have yours fixed. Find a better source for information on your car than a junk yard.

How often has the cooling system been maintained on that 94? If you read the post above you'll know that the system should have been drained and fresh coolant installed every 2-3 years/24-32,000 miles. So yours should be on the 4th or 5th coolant change by now at the very least. Ever service the coolant to keep the corrosion inhibitors intact?

The BarsLeaks or GM coolant supplement should be in the system already. It's required for the engine per the GM service manual procedures. Why wait to put it in now after there's some sort of problem?

Another thing you might want to do is to pressure check the cooling system to see if there's a leak somewhere that only shows up under pressure that could have caused the coolant loss.

RLLOVETT
03-21-04, 01:51 PM
Thanks for the words of wisdom! The following link http://www.tpub.com/content/construction/14264/css/14264_227.htm makes it sound like irrepairable harm will be done if the car is driven with combustion gases in the coolant...I guess the question is:How long before damage is done? Other details on my problem: I changed the coolant and added Barsleaks as soon as I got the car and it ran fine through the summer until very recently when I got a couple of Low Coolant messages and topped it off. This recent overheating episode was NOT preceded be a low coolant warning. I'll try asking at the local speed shop for a mechanic although the dealer I mentioned before (Frost) has an ok rep...there used to be a young mechanic from their shop that started posting on this(?) board--are you out there?

Anthony Cipriano
03-21-04, 10:00 PM
Thanks for the words of wisdom! The following link http://www.tpub.com/content/construction/14264/css/14264_227.htm makes it sound like irrepairable harm will be done if the car is driven with combustion gases in the coolant...I guess the question is:How long before damage is done? Other details on my problem: I changed the coolant and added Barsleaks as soon as I got the car and it ran fine through the summer until very recently when I got a couple of Low Coolant messages and topped it off. This recent overheating episode was NOT preceded be a low coolant warning. I'll try asking at the local speed shop for a mechanic although the dealer I mentioned before (Frost) has an ok rep...there used to be a young mechanic from their shop that started posting on this(?) board--are you out there?


Pretty much all BS in that link. Running the engine with "combustion gases" in the coolant might eventually hurt something - if they're really there. I would doubt seriously if any harm will come from it, really.

I know an individual who's driven his Northstar for about 100,000 with a known head gasket leak. He just keeps adding 50/50 premix when low and pumps the BarsLeaks to it. He just doesn't want to rip into it until it's really dead. That and he was curious as to how far it would go with the head gasket leaking. It would blow the coolant out of it and overheat sometimes and then he started using the Barsleaks in copious amounts and the symptoms lessened - and lately have disappeared. Seems to have "healed" itself. I'm sure it didn't but the point is that that engine in specific has run for years with a known head gasket leak and is fine otherwise. Keep it full of coolant and double the BarsLeaks concentration and you can probably drive it forever. The main thing is to keep the system full of the sealant so that it'll stop any coolant leaks into the cylinder when the engine is shut off so that you don't flood a cylinder and suffer a hydrostatically locked cylinder.

RLLOVETT
03-22-04, 12:17 AM
That is not just a LOL but a whole LOLly column! Your guy sounds like a man after my own heart, so I will gleefully fillerup with 50/50 and Barsleaks until the cows come home! Many thanks, as always, Anthony, for your sage advice!

Aurora By Olds
03-22-04, 10:12 AM
Pretty much all BS in that link. Running the engine with "combustion gases" in the coolant might eventually hurt something - if they're really there. I would doubt seriously if any harm will come from it, really.

I know an individual who's driven his Northstar for about 100,000 with a known head gasket leak. He just keeps adding 50/50 premix when low and pumps the BarsLeaks to it. He just doesn't want to rip into it until it's really dead. That and he was curious as to how far it would go with the head gasket leaking. It would blow the coolant out of it and overheat sometimes and then he started using the Barsleaks in copious amounts and the symptoms lessened - and lately have disappeared. Seems to have "healed" itself. I'm sure it didn't but the point is that that engine in specific has run for years with a known head gasket leak and is fine otherwise. Keep it full of coolant and double the BarsLeaks concentration and you can probably drive it forever. The main thing is to keep the system full of the sealant so that it'll stop any coolant leaks into the cylinder when the engine is shut off so that you don't flood a cylinder and suffer a hydrostatically locked cylinder.
I ran mine for 20k+ with one gasket totally blown, and the other leaking. Never once did it reach temps above 205 down the highway, and 220 when idling. I never used bars leak or anything...maybe I should have. I just decided to finally tear it down while I had the time and money to do it. Very impressive if you ask me.

dloch
03-22-04, 04:07 PM
I know an individual who's driven his Northstar for about 100,000 with a known head gasket leak. He just keeps adding 50/50 premix when low and pumps the BarsLeaks to it. He just doesn't want to rip into it until it's really dead. That and he was curious as to how far it would go with the head gasket leaking. It would blow the coolant out of it and overheat sometimes and then he started using the Barsleaks in copious amounts and the symptoms lessened - and lately have disappeared. Seems to have "healed" itself. I'm sure it didn't but the point is that that engine in specific has run for years with a known head gasket leak and is fine otherwise. Keep it full of coolant and double the BarsLeaks concentration and you can probably drive it forever. The main thing is to keep the system full of the sealant so that it'll stop any coolant leaks into the cylinder when the engine is shut off so that you don't flood a cylinder and suffer a hydrostatically locked cylinder.
I have also doubled the Barsleak in mine and after the car was driven at temp for an extended period of time the leak has stopped..... I'm affraid to really lay on it for fear of blowing out the plug so to speak..... I will try that when I have the other engine done and I'm ready to make the swap....

ogremo1922
03-24-04, 10:06 PM
My $40,000.00 ETC POS is 2,000 miles out of warranty with what the dealer has described as "Stretched Head Bolt threads" some BS term for a blown head gasket and pulled threads. I have read all of the posts regarding this matter and as for this being a forum for complainers that don't maintain there vehicles, well, my reply to that would be, bite me! This car has been a pain since day one, built by over paid crack heads on a Saturday morning following a long Friday night. This car has been nothing but problem after problem. The Northstar is a fine example of piss poor engineering. I am in fact an Aerospace engineer and work with materials that most people don't even know exist. Aluminum is a very common aerospace material due to weight restrictions, so here is the million dollar question. Have you ever heard of Helicoil? Every component manufactured out of aluminum that has threads no matter the size, should be inserted to maintain the strength and integrity of the thread and prevent corrosion (etching) from mating materials such as aluminum and steel. Any engineer walking the planet that didn't sleep drink or smoke his way through school will tell you this. The real question would be "why didn't the GM engineers that did the design work on this joke put helicoils in the block?" Easy answer, because they cost $0.60 an insert and hell, the engine wonít fail while itís under warranty so itís a win win situation. The real kick in the teeth is that the new engine that GM is willing to supply at that bargin price of $9,000.00 has thread inserts installed in it. I now own a car that will require a $9,000.00 engine according to the dealer, none of which GM is willing to pick the tab up on of course and my car has been maintained meticulously. Go figure. Face it there's a reason Cadillac has such a piss poor resell value, itís an overpriced KIA with a nice interior and a cool emblem. Disposable POS!

Anthony Cipriano
03-25-04, 02:30 PM
My $40,000.00 ETC POS is 2,000 miles out of warranty with what the dealer has described as "Stretched Head Bolt threads" some BS term for a blown head gasket and pulled threads. I have read all of the posts regarding this matter and as for this being a forum for complainers that don't maintain there vehicles, well, my reply to that would be, bite me! This car has been a pain since day one, built by over paid crack heads on a Saturday morning following a long Friday night. This car has been nothing but problem after problem. The Northstar is a fine example of piss poor engineering. I am in fact an Aerospace engineer and work with materials that most people don't even know exist. Aluminum is a very common aerospace material due to weight restrictions, so here is the million dollar question. Have you ever heard of Helicoil? Every component manufactured out of aluminum that has threads no matter the size, should be inserted to maintain the strength and integrity of the thread and prevent corrosion (etching) from mating materials such as aluminum and steel. Any engineer walking the planet that didn't sleep drink or smoke his way through school will tell you this. The real question would be "why didn't the GM engineers that did the design work on this joke put helicoils in the block?" Easy answer, because they cost $0.60 an insert and hell, the engine wonít fail while itís under warranty so itís a win win situation. The real kick in the teeth is that the new engine that GM is willing to supply at that bargin price of $9,000.00 has thread inserts installed in it. I now own a car that will require a $9,000.00 engine according to the dealer, none of which GM is willing to pick the tab up on of course and my car has been maintained meticulously. Go figure. Face it there's a reason Cadillac has such a piss poor resell value, itís an overpriced KIA with a nice interior and a cool emblem. Disposable POS!


If you knew your ass from a hole in the ground you'd know that a "helicoil" will not support high loads like a head bolt thread. It takes a single piece insert like a timesert to perform the task. If you're using helicoils in airplane construction let me know the make and model so I can stay off it.

Any info on the model year ETC and maintenance of the cooling system and such? If the diagnosis is 'stretched head bolt threads" then I'd think that you would have a good case for an "extended warranty" consideration as obviously the head bolt threads didn't just 'stretch" overnight. It must have been happening from day one. Explain the phenomenon of aluminum thread creep and such in aerospace terms to them and I'm sure they will understand.

Airplanes cost hundreds of millions of dollars and must be operated and maintained by qualified personel to a specific duty cycle. It's easy for aerospace engineers to specify something that wont fail and that costs an arm and a leg when they know the duty cycle and have no budget or competition. Not so with car engines.

Anthony Cipriano
03-25-04, 02:51 PM
Every component manufactured out of aluminum that has threads no matter the size, should be inserted to maintain the strength and integrity of the thread and prevent corrosion (etching) from mating materials such as aluminum and steel. Any engineer walking the planet that didn't sleep drink or smoke his way through school will tell you this.


Keep in mind that these inserts into the aluminum used to prevent "etching and corrosion" - what are they made of to prevent this? Steel? Just like the bolts you mean? Why, if the steel inserts don't cause "etching and corrosion" due to dissimilar materials then why would the steel bolts cause it?

There are steel bolts in aluminum threads throughout the aerospace industry as well as the auto industry. Coatings are applied to the bolts to prevent the galvanic action where necessary and the joints are protected against intrusion from corrosive media where necessary. For the galvanic action to cause a problem between the steel bolts and threads there has to be some sort of conductive or corrosive electrolyte present. That is one reason that each Northstar head bolt is in it's own, sealed cavity in the block where is't nice and dry and clean and protected. But you knew this, right?

Go and look at every aluminum automotive engine out there in the market place and tell me how many "helicoiled" or inserted head bolt holes you find. I'll save you the time. None. Some how all those darn stupid automotive engineers manage to make those steel bolts live in those aluminum threads.

ogremo1922
03-30-04, 06:03 PM
I wasnít going to reply to your smart ass comments but then decided oh what the hell, youíre a moron so why not. First of all knower of all, If you knew your ass from a hole in the ground you would know Helicoil is a BRAND name no different than say TimeSert. A Helicoil insert would damn well hold the load of a head bolt, you have to be kidding me, a tapped hole in aluminum is going to hold the load of a head bolt but as you put it ďIf you knew your ass from a hole in the ground you would know that a "helicoil" will not support high loads like a head bolt thread. Youíre a fu**ing moron! To answer your really stupid question about the materials, the bushings are stainless or Inconel if the application requires it and inserted into aluminum, now the bolt going into the stainless bushing will be a high tensile strength steel like 8740 Chrome Moly or 17-4 Stainless thus eliminating the actual usable thread from being a tapped hole in a crappy aluminum casting. Oh yea LOL blow me! Youíre a pretty smart guy, not. You make me laugh with your ignorance, I forgot more about this crap last night while I was asleep than youíll ever know.
Stick with flipping burgers; I'm sure youíre great at it.

Helicoils use is the standard per NASA, Civil and Military Aerospace and a whole load of Mil Specs but you donít agree. Thanks for sharing you stupidity.

Heli-Coil is the approved Screw-Lock Screw Thread Insert source for Boeing Aircraft per specification
BACI12AE rev B

Bi-Directional Design: Installs quickly and easily from either end.
Stronger Assemblies: Tapped threads are strengthened because the inherent flexibility of the insert provides a more balanced distribution of static and dynamic loads throughout the engagement length.
Eliminate Stress: Virtually no stress is induced into the parent material as no staking, swaging, or keying in place is required.
Positive Self-Locking Torque: HELI-COIL Tangless screw-lock inserts provide a positive, self-locking torque complying with the requirements of Mil-I-8846.
Minimize Space and Weight: Requires smaller boss than solid inserts; minimize total in-place cost.
Conform to NAS1130

Anthony Cipriano
03-30-04, 11:57 PM
Let's dispense with the name calling. I apologize for my indescretions. I got caught up in the moment of reading your diatribe and responded inappropriately. Based on your comments I guess I thought you'd understand. Based on your reply maybe you did.

Helicoils are different from Timeserts in the manufacturer and the design of the insert. They aren't the same thing and "helicoil" is not a generic name for any thread insert that you happen to come across.

I doubt that you have forgotten more about this than I know. Seriously. I have worked on these engines for as long as you've worked on your airplanes - probably longer - and I've worked specifically on the head bolt and head gasket interface in aluminum block engines. I know a fair amount about threads and threaded fasteners myself.

Sorry to burst your bubble but I never flipped burgers and if I had it would have been decades ago back when McDonalds was only in the "millions sold" and flipping burgers was something to aspire to.

I've personally done thread strength tests on the head bolt thread repairs with a variety of different thread repair mechanisms and I can assure you that helicoil brand inserts are no where near as strong as the prescribed Timesert brand inserts. Specifically the Timeserts designed for the Northstar engine head bolt repair. The application specific Timeserts were developed with Time Corp. and validated for the Northstar engine.

The single piece Timeserts are much stronger in the repair of threads in parent metal aluminum as the single piece insert will spread the load of the bolt threads over the entire OD threads of the insert. The information you quoted sounds like a regurgitation of the helicoil repair manual. The fact is that when helicoils are installed in aluminum and a very highly loaded fastener is installed in the repair some of the threads are loaded more than others. Those higher loaded threads start to fail and the thread "overloading" spreads to the next higher loaded thread, etcetera until the whole insert pulls out. Plus, there's no such thing as a Helicoil that is as long as the Northstar female treads. Nor was there a Timesert that long until the application specific insert for the Northstar headbolt threads were developed. Time learned a little about their inserts in the process of developing them. Throw out your fastening textbooks for something as highly loaded as a headbolt in aluminum. You need more than the textbook 1.5 diameters. You need at least 2.5 diameters for the joint to live through thermocycling, so the available Helicoils wont work as they aren't long enough and because the very feature you tout causes the joint to eventually fail on the OD of the insert - proven time and time again. You're arguing with the wrong guy on that point. The Timeserts are the only way to go. That's why they're specifically called out in the GM service manuals for the Northstar engine and why the GM specialty tool supplier KentMoore stocks the Northstar specific repair kits and inserts.

If your failure occurred as you described I would again say that you have a good case to ask Cadillac Customer Service for some dispensation in the repair. If you approach the service department and Cadillac with the same attitude as above I can prodict the results, however.

Somehow in your comments back to me you managed to sidestep the issue that you brought up in the first place. You mentioned the stupidity of the engineers that designed the joint without inserts and the "etching and corrosion" of the steel bolts against aluminum. I still assume that you're referring to galvanic corrosion causing problems. Inserts wont prevent that. Maybe this is why you conveniently forgot this this time around and just mentioned high tech terms like chrome moly or stainless steel. So what? Galvanic action would still weaken the joint if that were a problem, even with an insert. It isn't an issue because of the fact of the coatings on the bolt and the fact that the high stress joints are protected from any corrosive media.

Race engines and aircraft use inserts frequently not necessarily because of strength of the thread but because of wear in the aluminum threads due to frequent dissassembly for inspection and subsequent reassembly. Head bolts are generally a one shot deal for an engine as 99% of the engines produced will never see any service at all on the head bolts. So, inserts just don't make sense for all engines like they may in some applications on aircraft. An inserted joint is not necessarily stronger, it'll be more wear resistant. But why would it be stronger if the aluminum threads are good and the bolt threads are sound??

Honestly, if Boeing thinks that Helicoils are as strong an insert as is available or that they are stronger than Timeserts in aluminum then they are sadly mistaken. The one piece inserts by Time have proven to be stronger in parent aluminum in many different tests. Maybe the helicoils are good enough for aircraft but they wont hold a head bolt in an aluminum block. This misconception is one of things that causes many shops to have a poor opinion of the Northstar engine. After damaging a head bolt thread they "fix" it with a helicoil only to have the bolt pull out when torqued. So, they claim it's a "throwaway" and "irrepairable". If they had used the correct inserts the repair would have been very simple, easy and elementary. Why can't they read the service manual?

Sorry you're having trouble with your Eldorado. Still no idea of the year or mileage for a clue as to what went on here...

Anthony Cipriano
03-30-04, 11:59 PM
By the way. Do you know why there's an "e" in Boeing? So when they hit the ground they don't go "Boing". Lighten up and live longer.

ogremo1922
03-31-04, 07:16 AM
You're Right; this has been the most depressing car purchase I've ever made. I have waited years to purchase an Eldorado and to say the least itís not been a good experience. The burger flipper and moron comments were out of line and I'm sure you're fantastic at whatever you do. I apologize for those, I to got caught up in the moment. As far as the E comment in Boeing, I will be using that today. Thanks

zonie77
03-31-04, 08:57 AM
In the May 2004 Hot Rod Magazine, Pit Stop column (page 100) Marlan Davis gives an explanation of 'torque to yield' fasteners and torque angle meters. I don't know if they'll have it on the web site.

Anthony Cipriano
03-31-04, 10:12 AM
You're Right; this has been the most depressing car purchase I've ever made. I have waited years to purchase an Eldorado and to say the least itís not been a good experience. The burger flipper and moron comments were out of line and I'm sure you're fantastic at whatever you do. I apologize for those, I to got caught up in the moment. As far as the E comment in Boeing, I will be using that today. Thanks


Back to your original problem. What are the symptoms that your engine is exhibiting that cause you to think the head gaskets may be leaking and/or the head bolt threads are failed? Not to say that it doesn't ever happen but there are millions of Northstar engines running around out there holding the head bolts just fine. Either something happened or it isn't the head bolts. I have diagnosed a number of overheating and leaking problems that were originally diagnosed with head gasket failure/head bolt stripping that turned out to be something simple. Anytime there is any sort of problem with the Northstar engine the techs and service writers and independent garages love to jump to the conclusion that it's the head bolts/head gaskets. Since that is about the only thing that really seems to go wrong with the engine that is all they have to fall back on I guess.

In reality most actual head bolt problems come when the engine is dissassembled for some reason or serviced and a head bolt strips on reassembly - sometimes due to wear, mostly due to the wrong assembly techniques and often due to the tech cleaning the block threads out with a cutting tap. All the threads in the aluminum block are rolled threads (forged in effect by coldworking the material rather than cutting) and they're a very tight thread class - for maximum strength and engagement. When a cutting tap is run through them it removes some of the thread effectively ruining it. Then "of course" it's the fault of the block or the stupid engineers. Common failure mode.

If, indeed, your problem is the head bolts for some reason it's almost a gimme repair to remove the heads, timesert the block and reinstall the heads. No where near $9000.00. You need to find a dealer or mechanic that's willing to work on the engine and is more interested in fixing your engine than scaring you into buying a new car or a Lexus from his Lexus store next door. Some of the dealer tactics obvious on this forum are despicable. They're definitely after the short term gain. The most favorite is what you're in the middle of, I suspect. Trade in your "worthless" car for a new one and we'll give you a deal. And in two days your car is on the used car lot (fixed for nothing) for sale for big bucks. The Northstar engine is extremely robust and repairable. The timesert kits for the head bolts are readily available, easy to use and extremely effective. As you point out, an inserted hole (with timeserts) is as strong or stronger than the original hole. You just need to find a reasonably adept mechanic with the correct service manuals and the willingness to read the instructions.

You got some bad information. First, the dealer is really trying to soak you/scare you with the $9000 engine. They don't cost nearly that much. Second, the new GM Northstar engines don't have inserted blocks. Some rumor that is. There are no inserted engines coming out of the GM plant for new or service applications. I've mentioned it before, I have family that works there. I know. The service engine supply is assembled out of new parts and the new blocks are machined on the same equipment that the original blocks were. Someone is really going to lenghts to make their story sound good to you. Unfortunately, they got their facts wrong.

There's not a reason in the world that your existing engine can't easily be repaired and be as good, or better, than new, if indeed there is a problem in that area.

Also. Let me clearify something. When talking about corrosion and inserts and such, my comments were made in regard to the insert to parent metal interface. Certainly, there will be no issue between the steel bolt and the insert (whatever it is made of) but there will still be an issue of galvanic action if an electrolyte is present between the insert and the parent aluminum on the OD of the insert. That can be a big problem in itself in many applications. Most all of the galvanic action between the aluminum and steel bolts can be controlled by isolating the heaviest loaded critical fasteners and applying loctites and barrier coatings to the fasteners. Thread inserts are no panacea. They create on more interface to deal with that can fail.

Possibly the problems you have are in no way related to the had gasket. More information will help provide an answer.

I would still encourage you to contact Cadillac Customer Service. If all the facts are as you state and the engine really needs a major repair then I would expect them to provide some dispenssation for the problems. Cadillac has a history of being very accomodating for their customers. Remember that the dealer is an independent business. He sells Cadillacs. But is not Cadillac per se.

dloch
03-31-04, 11:23 AM
I would still encourage you to contact Cadillac Customer Service. If all the facts are as you state and the engine really needs a major repair then I would expect them to provide some dispenssation for the problems. Cadillac has a history of being very accomodating for their customers. Remember that the dealer is an independent business. He sells Cadillacs. But is not Cadillac per se.
I 2nd that. GM/Cadillac is in business to sell cars and keep there customers happy so they may some day buy another car from them, not piss them off and lose market share to Ford.. Lexus.. you name the manufacture.

bondz
03-31-04, 09:07 PM
:banghead: I have a 94 Concours and had alot of overheating issues last summer with my car,I had all the hoses replaced as well as the thermostat and now im expierincing overheating issues again

Anthony Cipriano
03-31-04, 09:20 PM
:banghead: I have a 94 Concours and had alot of overheating issues last summer with my car,I had all the hoses replaced as well as the thermostat and now im expierincing overheating issues again

Have you checked the water pump drive belt, the water pump drive belt tensioner, the vapor vent line for flow, the coolant concentration? All things that have been described recently to diagnose an overheating problem. Are you experiencing coolant loss ie. frequent need to add coolant or frequent, repetitive "low coolant warning" message? What about cooling fan operation? Do the fans come on and run when the overheating occurs?

What are the symptoms of your "overheating"? None of these things are rocket science, they basically apply to all cooling systems, Northstar or otherwise and all have been detailed many times before on this forum - most very recently. Pounding your head against the wall will not solve the problem. Diagnosing the problem will. Get with it and post back more info.

bondz
03-31-04, 09:27 PM
perhaps pounding my head against the wall was the improper choice I apologize,please understand I love my car I was just stating that I ve had this issue addressed by professional techs and have had a repeat of the problem. maybe my problem is my mechanic???

Anthony Cipriano
03-31-04, 09:36 PM
perhaps pounding my head against the wall was the improper choice I apologize,please understand I love my car I was just stating that I ve had this issue addressed by professional techs and have had a repeat of the problem. maybe my problem is my mechanic???

I think that you may have hit on the problem. No pun intended. :p Any mechanic or technician that knows basic automechanics should be able to check the items listed above, as well as pressure check the sytem for leaks to diagnose the problem. In fact, they should be explaining to you how they're going to diagnose the problem. If you have overheating symptoms then there's obviously a cause - someone just needs to isolate it and correct it. Ask them to check the above items for starters.

Olds3.5
04-01-04, 11:27 PM
This forum, and specifically this thread, has been very interesting to me. However, there is still much left unanswered with respect to the original question and points made about engineering steps taken to make aluminum threads perform better (longer). Specifically, how many people experience head gasket failure? At what age and how many miles? What do other industries (aerospace, airline) and other car manufacturers (Honda) specify in order to address this issue?

With respect to this topic, I would like to explain one of the main reasons that I am participating in a Cadillac forum when I own an Intrigue. I heard about a fellow shortstar owner with a head gasket problem and the word "helicoil" was mentioned. So I did a google search and arrived at this interesting forum basically as a result of that information search. Although I was unfamiliar with a helicoil, I am very familiar with head gasket failures. Being indirectly associated with the automotive repair industry, and professionally involved in QA/QC, I have seen head gasket failures occur in many different cars of many different brands throughout the years. My last car, an 89 Sable with a 3.8L engine (alum heads, cast iron block), experienced a head gasket failure at 163k miles. (Yes, the honing marks were still visible on the cylinder walls.) The total cost was about $600 and yet I did not feel like Ford did not give my money's worth with respect to product quality. Can you see why? First, 163k is a lot of miles and I was no longer paying notes on the car. Second, and more importantly, $600 bucks seemed reasonable for the repair.

Presently, my car has 72K miles and I find myself wondering if I should keep this car because the possibility of the head gasket failure occurring too soon and costing too much.

How soon (or often) is too soon or how much is too much? Based on what? Since these terms can can be ambiguous and based on personal opinions and value judgements, I will offer a standard by which to make this determination:

The more expensive the repair is likely to cost, the less frequently it should be likely to occur.

It seems intuitively obvious but I wonder how many engineers and designers take this into consideration (outside of the Japanese). Can you imagine getting a brake job after 50K miles and being handed a bill of $4K? If a brake job is going to cost that much, then it better damn well occur very infrequently, if not last the life of the car. If a starter is going to be located in the valley between the cylinder banks and it's going to cost that much more to R&R, then design a starter that lasts that much longer. With respect to the head gasket/timesert repair of the N* engine family, the repair is an expensive one. Therefore, it should occur infrequently, if at all. To see the level of concern and discussion on this repair, how early and frequeltly is occurrs and the anger/ venting of some people provides feedback and information enough for me draw a conclusion. How often is too often and based on what? Based on the expense of the repair, that's what! Therefore, based on the expense of the repair, It is my judgement that the head gasket failure occurs too often and/or too soon.

Anthony Cipriano
04-02-04, 12:01 AM
I would tend to agree with you except for the fact that I believe the head gasket and head bolt issue with the Northstar is blown out of proportion several ways:

First, many references to the problem show up on this and other internet forums because the forums tend to attract people that have problems. There are millions of Northstars running around without a head gasket problem and you never hear from them. Obviously many of the ones that do have a problem show up on internet forums for help and to vent.

Two, most of the head gasket failures do show up at high miles as you described with your Ford. That is why I mentioned earlier that the Northstar is it's own worst enemy, in a way. About the only thing that really goes wrong with it, even at high miles, is a head gasket occasionally. The rest of the engine is pretty bullet proof and, aside from nuisance oil leaks at high miles, the head gasket is about the only thing people complain about. As any engine reaches higher miles something has to start to wear and go away. The head gasket in an all aluminum engine takes a lot of stress, no question, and, depending on the climate, the duty cycle, the number of thermocycles on the engine it is not inconceivable that over 100,000 some head gaskets are going to start showing up.

Three, the repair is way overbolwn. As many people on this forum have experienced the head gaskets can be replaced relatively easily. The engine is completely repairable with new gaskets and timeserts for the head bolt holes if required. This is way different from the "the engine is scrap" or "the engine is a throw away" or "a new engine is required" type of story that many people get as a scare tactic to buy a new car instead or because the mechanic doesn't know how to fix it.

Four, many of the head gasket repairs turn into nightmares because of improper mechanical work, using helicoils for repair of the head bolt holes instead of the correct timeserts, etcetera.

Five, the engine needs head gaskets for some reason and the mechanic chases the head bolt holes with a tap (ruining the threads) or uses the wrong tensioning method, or puts grease, oil or antiseize on the head bolt threads and strips the head bolts out - instantly turning a normal repair into a nightmare.

Six, as mentioned, the 93, 94 and 95 engines are more prone to high mileage head gasket failures due to the fact that they were originally filled at the factory with the green, silicated, conventional coolant which required frequent replacement to keep the corrosion inhibitors at full strength. If the cooling system was not maintained the head gaskets will rot from the inside out and fail. Then see item five above.

I am not trying to make excuses for any head gasket failures but I don't think they're as prevalent as the internet forums indicate nor do I think that they're nearly as difficult to deal with as many folks seem to experience. I don't know how to correct the latter except by trying to get as much of the correct information out to people as possible.

The designers of the engine did understand that a head gasket is a major repair and not something that a customer should have to deal with on a regular basis. That's why so much work went into making the head gasket as robust as possible and repairable as possible when there was a problem. It's specifically what drove the development of the "loss of coolant" protection scheme that modulates cylinder operation to protect the engine in case of severe overheat or coolant loss. The head gaskets are the first thing damaged in an aluminum engine when it overheats so the protection scheme was developed for the Northstar to prevent that occurance.

I would honestly not worry in the least about your 3.5 V6 Shortstar. That engine is one of the most bulletproof engines around and has absolutely no history of head gasket problems. Plus, all the shortstars were assembled and filled with the DexCool long life coolant that eliminates any worry about lack of cooling sytem maintenance.

Olds3.5
04-02-04, 10:10 AM
Anthony, thanks for the feedback. You have given much helpful advice at this site. In fact, you are more like a consultant, given your indepth knowledge and the professional detail of your responses. I notice that you use the word "validation" in some of your responses when you talk about R&D of the N* engine. I am not sure what that means in engineering terms. To me, the only true validation is customer satisfaction, sales, profit, success. I don't have an engineering degree but I do have an MBA. I have been taught that quality is defined as "conformance to requirements". Who's requirements? The customers requirements, of cource. I am not sure what criteria R&D engineers use to determine but it seems to me there is not enough imput or feedback from the real world experiences of the comsumers when the validation criteria of the engineers fail to reflect the validation criteria of the real world. For example, the 3.1L/3.4L v6s are notorious for lower intake manifold gasket failures around 60K miles. I have known about this for years and specifically avoided buying this engine for this reason. The repair costs about $500. GM finally got rid of this problem with the 3.5L v6 found in the 2004 Malibu. The 3800 Series II engine (FWD, naturally aspirated applications only) has a problem associated with the plastic intake manifold. In the vicinity of the EGR, the gasket breaks down, allows coolant to seep into the engine and causes hydro-locking of the engine (or worse). I have known about this problem for years and specifically avoided that engine. (Yup, I went with the shortstar in 2001.) Finally, GM decided to make the intake manifold using aluminum to solve the problem. What took GM so long? Is there some feedback mechanism that lets you know when your validation criteria lack validity? That is why I am suspicious of the use of the word validation when the validation is performed and determined in-house. Validation criteria start with the consumer and it is R&D's job to define and reflect them. There should also be a feedback loop that lets R&D know very quickly when those criteria are not sufficient. At gm, that feedback loop seems to be very slow.

Anthony Cipriano
04-02-04, 12:04 PM
Anthony, thanks for the feedback. You have given much helpful advice at this site. In fact, you are more like a consultant, given your indepth knowledge and the professional detail of your responses. I notice that you use the word "validation" in some of your responses when you talk about R&D of the N* engine. I am not sure what that means in engineering terms. To me, the only true validation is customer satisfaction, sales, profit, success. I don't have an engineering degree but I do have an MBA. I have been taught that quality is defined as "conformance to requirements". Who's requirements? The customers requirements, of cource. I am not sure what criteria R&D engineers use to determine but it seems to me there is not enough imput or feedback from the real world experiences of the comsumers when the validation criteria of the engineers fail to reflect the validation criteria of the real world. For example, the 3.1L/3.4L v6s are notorious for lower intake manifold gasket failures around 60K miles. I have known about this for years and specifically avoided buying this engine for this reason. The repair costs about $500. GM finally got rid of this problem with the 3.5L v6 found in the 2004 Malibu. The 3800 Series II engine (FWD, naturally aspirated applications only) has a problem associated with the plastic intake manifold. In the vicinity of the EGR, the gasket breaks down, allows coolant to seep into the engine and causes hydro-locking of the engine (or worse). I have known about this problem for years and specifically avoided that engine. (Yup, I went with the shortstar in 2001.) Finally, GM decided to make the intake manifold using aluminum to solve the problem. What took GM so long? Is there some feedback mechanism that lets you know when your validation criteria lack validity? That is why I am suspicious of the use of the word validation when the validation is performed and determined in-house. Validation criteria start with the consumer and it is R&D's job to define and reflect them. There should also be a feedback loop that lets R&D know very quickly when those criteria are not sufficient. At gm, that feedback loop seems to be very slow.

Once again, I don't totally disagree with you, but, for the sake of the arguement, consider the fact that, in general, the vehicles we're talking about here are at least 4 to 5 years old and most are approaching 10 or more years old. Almost all of them discussed in the forum have near 100,000 miles on them or well over 100,000 miles. These are not exactly new cars. Most are on their 2nd, 3rd, or 4th owner and a distressing number of them seem to have unknown histories coming off ebay or other sources. I read a lot of posts on a lot of forums and this seems to be the trend. Naturally, there are some people that bought the vehciles new, but most are well up in miles and age and are hand-me-downs. This "feedback" on head gasket issues and such applies to an engine that was designed in the late 80's, when most people's expectations of a vehicle's life was in the 100,000 mile/10 year range.

As I've mentioned before, the Northstar, these FWD Cadillacs and most of the newer cars are being their own worst enemy in a way. They're exceeding the useful life that was considered "normal" 20 years ago. They still look good (cured the rust problem), the interiors are still nice (despite GM's reputation for "cheap" interiors they do seem to hold up over the long haul) and the engines still run good even out at 150-200,000 miles and further.

It seems to me, that poeple's expectations are rapidly changing to the effect that they now expect the car to "live" with no problems for over 200,000 miles. Yes, this feedback is recognized and taken into consideration. Even the emission certification these days automatically assumes that the vehicle will run for 100,000 miles and be in complete compliance and many certification strategies are based on 150,000 miles of service with 100% of vehicles in compliance.

Every single vehicle out there has some sort of "issue" that starts to show up over 100,000. Read the internet forums for different brands and you'ill come to the same conclusion. Not to deflect criticism from the Northstar head gasket issue, but to use as an example, the 92, 93 and 94 LS400 Lexus engine doesn't seem to have head gasket problems. But it has an annoying tendency to pitch the elastomeric timing belts at 100,000 miles and bend the valves if you don't replace them. So every older Lexus (actually all of them, older or not) needs to automatically have the timing belts replaced at 100,000. A $1300-$2000 charge based on who you believe or quote. So, in comparison in this case some Northstars need head gaskets while all Lexus engines need timing belts. The Lexus timing belts are a source I use because this is an example of the thinking that went into the Northstar for customer satisfaction. The Northstar has a chain timing drive that easily lasts the life of the car/engine. It'll go 300,000 miles or more with no service or maintenance. So, no belts to change or break.

All manufacturers have things like this show up in their vehicles/engines and on the appropriate internet hate sites. BMW has an issue with some serious oil consumption and, several years ago, endured huge warranty costs on whole engine replacments due to the Nikasil coating on the cylinder bores. Toyota has the infamous engine "sludging" failures due to an inadequate PCV design, Ford Taurus SHO Yamaha V8s have the timing gears falling off the cams. I don't mention these to throw stones at all - just to point out the myriad of problems that show up in the field and to illustrate the fact that, despite all the developement and validation testing, it's hard to factor "father time" into acclerated testing and to predict all of the customer use cycles, fuels, lubes, maintenance schedules, etcetera that the engines will be subjected to.

This goes full circle to my original comment about the age and mileage on most of the Northstars in these discussions as the accelerated testing that was done on the engine to simulate 150,000 miles back in the late 80's and early 90's probably didn't exactly duplicate what's being seen on some of these vehicles. But how does a manufacturer "wait" for 10 years to factor father time into the testing accurately?

The definition of "validation" means different things to different people and will also mean different things to, say, an engineer and an MBA. I think you're just talking semantics. Actually, that could be a doctorial thesis maybe. "The Meaning and Definition of Validation..."

To the engineers the design is done, modeled, tested and "development" testing confirms that functions act and work as deisgned and expected ie. The connecting rods don't break, the engine doesn't go into preignition, the power levels are as expected... There are various levels of development in any program from "proof of concept" engines to mules to Alpha, Beta, etcetera... until the program is ready and released for production. At each stage there are certain levels of development and validation testing to confirm that the vehicle/engine meets the design goals and the customer requirements as they were laid out at the beginning of the program and converted to accelerated testing bogeys in most cases. At some point the tooling and machinery in the plant is ready, the engine parts are ready and you have an engine that is completely finished off the production process and production tooling and the final validation battery of testing confirms that the parts off the production process are the same as the early prototype test parts.

There is always more to learn about how to replicate the customer requirements in accelerated testing. I am sure (tongue in cheek) that Toyota learned more about accelerted PCV testing and PCV icing after the "sludging" failures were recognized and diagnosed in the field. There's always more to learn about head gaskets and head bolting and block casting. All the feedback that's being gained with field failures is constantly being put back into the accelerated validation testing, yes. The trouble is, it doesn't "fix" the 6 or 8 year old engines that are out in the field before this learning takes place. No way to make that learning retroactive to the vehciles we're learning from. So, the posters on this forum in 5 or 10 years that are driving 150,000 mile 03 Devilles or SRX's willl undoubtably have something to bitch about. But it probably won't be head gaskets or head bolts. ;)

Olds3.5
04-02-04, 02:54 PM
Yes, the expectations of the consumer have risen dramatically and it amazes me how well today's vehicles perform. In fact, I think that people's expectations have become rediculous, especially with respect to horsepower. My sister's new Accord 3L v6 makes more hp than the Corvette of a generation or so ago. I can't tell you how many times I have heard of people wanting to find a way to remove the electronic top speed limiter, as if 120 mph wasn't fast enough. Competition, that's what it is and this is a hyper-competitive industry.

I do love the fact that the N* engines have a lifetime timing chain system. Very satisfied, overall, with my car. Much to like. Not only is rust no longer an issue, but the paint on my four year old car is way better than any car I have previously owned. The 89 Sable had a crap paint job that Ford did not stand behind.

With respect to the meaning of the word validation, maybe I didn't express myself very well. I am not trying to make an issue of the semantics of the word but the use of the word. I am not in a position to know what that validation is when you (Anthony Cipriano) use the word since I don't know what the validation criteria are. Using the word in that way does not explain much to me unless I accept the validation process on face value and take your word for it. If something seems to not working right and someone says that it that it has been validated, I may not accept that explaination at face value since I am having the problem. I tend to be a challenger.

However, I can't help but notice that you are a virtual expert on the subject of the N* so maybe that is why no one has previously challenged you on this before. When you said it has been validated, then prople accepted that it must be valid out of recognition and respect for your expertice. But what happens when the Firestone engineers say that their tires have been validated for safety and the Ford engineers say that the Explorer has been validated for safety? Whom do you trust?

Anthony Cipriano
04-02-04, 03:49 PM
Once again, I think you're placing too much emphasis on the actual word "validation". To me, it's obvious that it'll mean different things to different people. No one can make a blanket statement that something is "validated" against everything. And, it's certainly fair to ask how it was validated. To me, however, it's just as important to ask what quality control was in place to make sure that the validated design was manufactured as intended. Changing the manufacturing process or materials can change the validation that was done or render it moot.

The example of the Firestone tires you mention is a good one for discussion. I have no doubt whatsoever that the tire design and inflation pressures were validated by Ford engineers to meet the performance criteria for the vehicle they were placed on. It is ludicrous to me to assume otherwise considering that those very engineers buy and use those vehicles to transport their families on a daily basis.

The fact that the tires might fail when run underinflated would raise the question of how the validation constraints were arrived at, what inflation levels the tires were tested at during the validation testing, what specific tests were run on underinflated tires, etcetera. This raises a completely different set of questions regarding the "validation" of the tires or maybe what should be included or is reasonable to assume in the "validation" of the tires.

If you were a tire engineer and the tires would run on the vehicle at GVW fat the recommmended inflation levels for 100,000 miles at high speeds with no problem at all (really simplifying here) wouldn't you consider that the tires were "validated"? I think this is reasonable to assume. So now run the tires are 2psi low. Should they live? What about 4psi low? 6psi low? 20psi low? At some point the tires are flat and will not function. At some level the tires will be so low that they'll overheat and tread separation is an issue. What defines that point? If you can answer this you get the big prize. This illustrates the inherent problem with any validation testing of any product.

The product is validated to a certain set of standards defined by it's intended use assuming reasonable wear and tear and maintenance. Should the tires live at 2psi low? What about 20psi low? What's the break point?

Not that you asked, but my opinion on the whole Ford/Firestone deal is that the tires are fine and the vehicle is fine. The tires will fail when run underinflated. If they are run underinflated and then pumped up to the correct value they can still be damaged from the underinflation and fail later. The normal inflation pressure for those tires on that vehicle was probably a little closer to the "low inflation damage threshold" than other manufacturers would have placed it - just my guess here but based on engineering logic and what I read in the newspaper and trade publications. So, the tires get low, they sustain tread separation damage due to overheating at low pressure (severe sidewall flexure) at high speed and the tread comes off or just starts to flap and make noise and vibration. The driver swerves off the road, weaves side to side to figure out what is making the noise, panics and hits the brakes, etcetera causing the vehicle to go out of control. Lawsuit.

I have personally experienced tire blowouts on all corners of a vehicle at speeds up to 130mph as part of a high speed GM driver training program and can assure you that the car doesn't just fly out of control when a tire blows like this. It takes driver input to make it happen.

So no. The tires should not have "blown out" but, yes, they were "validated" to do what they were supposed to. Should there have been more cushion between the normal inflation pressure and the low pressure damage threshold? Maybe in hindsight, yes. Should the tires have been manufactured differently to increase their capability to run underinflated? Maybe in hindsight, yes. Hindsight is 20-20 so you get no points for being right here.

I don't think the Firestone tire issue has anything to do with "validation" per se but depending on your definition of "validation" I guess it could.

What was Ford's mistake that they were criticized for? Not that the tires or vehicle was poorly designed but that they didn't issue a warning when the data indicated that there was some sort of problem brewing.

Proof of this whole logic is that the only thing really fundamentally different out of all this was that tire inflation monitors are now part of the new vehicles on the market. If the tires were inflated correctly then there wouldn't ever have been a problem. The "problem" was not a validation issue as you can never figure how low a tire pressure to "validate" to. It was low tire pressure. Period. That was the simple root cause. It was addressed by low tire pressure warning devices that check the tire pressure for the driver and warn them when they're low. Next the lawyers will sue because the low tire pressure monitor doesn't disable the engine and fill the tire for the driver. :nono:

This is purely and simply my opinion on the tire issue and certainly should never be misconstrued as GM or Ford or anyone elses opinion. Just mine.

Keyth
04-03-04, 12:53 AM
Just a snipit about my '93 eldo..

Knocking on wood as I type.... I have not a head gasket problem on my 4.6 northstar and I'm going on 220,000 miles.. I've been very proud of the engine with exception to accessories (replaced alt twice now partly because of the lights I have and battery depletion but that's another story)... I have overheated my engine around 112000 miles when I got a hole in the radiator then went through a fast food line, smelled the boiling antifreeze, and thought it was the other guy... Not sure if corrosion or road debris played a part in that but I have not suffered any reproductions (IE blown head gasket) from it thanks to the nifty warning system and my eye on the temp gauge errr readout... I think synthetic oil played a part in saving me too..



That's my 2 cents..

zod
07-04-04, 06:37 PM
I have '98 model SLS with 55,000 miles.
Over the past half year I noticed that the coolant needed to be refilled several times with about a liter every time. The workshop could not find any fault.
Then in the beginning of February the heating suddenly disappeared an a few minutes later the engine temperature started to rise and fluctuate above the normal temperature to quickly travel close to the red. I stopped the car and the engine. A few minutes later, I started the engine again. Now the engine temperature quickly returned to almost normal. I drove to my garage after again having refilled the coolant, but now about a gallon. The garage again could not find anything wrong, not even after a 20-minute drive on the highway. No coolant was missing.
I now drove home, but after 5 miles, the same behavior returned, with fluctuating indicator needle, heat disappeared. When getting home I checked the coolant, which again was low by about a gallon. I refilled and returned to the garage. This time they did find exhaust gases in the coolant.
They believed it to be the head gasket(s).

Removing the entire engine and transaxle assembly to get to the head gasket, it was discovered that one of the gaskets was half way perforated at one of the cylinders, but the metal sealant around the actual cylinder looked ok. The head-bolts were all tightly pulled.

The conclusion was that the head gasket must have been bad quality, perhaps leaking for some long time. The care has not been driven hard.

The entire procedure cost $5000 to get fixed, including replacement parts and coolant. This car has been meticulously taken care of. No scheduled maintenance skipped and all fluid levels regularly checked.

Lack of maintenance was not the reason, but poor head gasket quality.
got the same car do you really have to Remove the entire engine and transaxle assembly to get to the head gasket????:confused: :rant2:

Anthony Cipriano
07-04-04, 06:57 PM
It's possible to pull the heads with the engine in the car but the general concensus on here is that it's easier to pull the engine.

JohnHume
03-14-06, 03:42 PM
I recently replaced the head gasket in my 1994 eldorado ($2000). The problem started as no heat for defrosting. My Mechanic flushed the system and everything felt hot yet still not a lot of heat for climate control. Then the engine started to overheat. At first we thought it was an air bubble so we removed the thermostat and still it over heated. We could not get any flow. No leak or squeal on the water pump. He did a co2 test on the new antifreeze and it showed positive. So he proceeded with the head gasket. He said that there were some signs of gasket failure, but it was still a little weird. When he was putting things back together he notice that the metal tube leading up to the water pump was rusted so he pulled the water pump. When he did this, he saw that all the fins on the pump were completely gone. This was something he had never seen in 25 yrs. The flush probable knocked off the last fin and that started the overheat problem.

I have heard from a couple of Cadillac friends of mine that the recommended AF is very corrosive. I checked with the original owner and he said that he had the car checked every Fall by a Cad Dealer. He could not say for sure that they flushed the system, but that is petty routine in the Northeast.

I know that the flush we did at the start of this problem, took two runs of Prestone flush and still everything was very brown.

Rob Benham
03-17-06, 01:37 PM
Following this thread through, it seems that I may be doing the wrong thing testing my car with plain water. I'm dumping the fluid so often that I did not want to keep wasting money. But would it makes so much difference.


Now, with new rad and stat, temps are swinging from 210 - 224, it's happening quickly and on a car than never varied more than 2 degrees f before changing rad. (it had a hole in it caused by the fan)

The bulk of the info is on "94 SLS ......bad streak" Thanks Rob

selinz
07-10-06, 01:16 AM
Becker and some others...
Your problem sounds to me as OBVIOUSLY a problem with the thermostat. When they get old and especially if they get warm, the begin to "stick" open or closed. If you see your temperature all of the sudden go lower than normal, it's sticking open and vice versa.
And as far as losing coolant, the most obvious place is old hoses. All should be replaced at 100-150K miles. The hoses don't leak visibly until they are under pressure. Then they blow little tiny pin holes so that steam leaks out. You may not see the leak unless the engine is HOT (as opposed to warmed up)

I was having all of these problems and told my cadillac dealer the issues and they said "we'll give it a complete lookover." Well, they said its $3500 and you need a new head gasket. I told them to forget that, just replace the thermostat and the lower radiator hose. Problem solved. Everything is working great and back to normal. Cadillac did not want to just replace the lower hose (I had already repaced the upper hose) and the thermostat. I think their mechanics get lazy and don't like to squeeze in there to do "minor" repairs because there is so little clearance. Yes, I do think that some mechanics are lazy (not directly dishonest, but they should realize that indirectly they are robbing cadillac of their reputation). Cadillac actually has one of the most sophisticated cooling systems on the market but thermostats and hoses can still fail. If you let the engine overheat or use the wrong coolant, you can mess up the head gaskets. But do yourselves a favor. If the system temperature fluctuates up and down, get the thermostat replaced!!! If you are losing coolant, change the hoses!

wisguy
08-12-06, 05:42 PM
I have a blown head gasket on my 1998 Eldorado which has a Northstar engine. Estimates to repair it have ranged from $2,000 to $4,000 and they won't guarantee their work. Many mechanics don't even want to touch the job. The car is in otherwise excellent shape.
My question is, do you know of anyone that has had success using products such as Thermagasket (Welcome to RX Auto. Makers of Thermagasket Industrial Head and Block Sealant (http://www.rxauto.com)) or any other similar type sealant?

dkozloski
08-12-06, 06:12 PM
There is no product known to man that will seal a blown head gasket. Bite the bullet and get out the wrenches.

Ranger
08-12-06, 10:03 PM
I have a blown head gasket on my 1998 Eldorado which has a Northstar engine. Estimates to repair it have ranged from $2,000 to $4,000 and they won't guarantee their work. Many mechanics don't even want to touch the job. The car is in otherwise excellent shape.
My question is, do you know of anyone that has had success using products such as Thermagasket (Welcome to RX Auto. Makers of Thermagasket Industrial Head and Block Sealant (http://www.rxauto.com)) or any other similar type sealant?
All of those products are also known as "Hope in a Bottle". Koz is correct. They don't work.