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14K views 58 replies 24 participants last post by  Ranger 
#1 ·
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.
 
#2 ·
JAvery20 said:
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?
 
#3 ·
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.
 
#5 ·
JAvery20 said:
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.
 
#6 ·
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.
 
#7 · (Edited)
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.
 
#8 ·
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 .
A search for “tension bolt” using Google returns 1690 hits.

My car did not have that problem though.
 
#9 ·
Anthony Cipriano said:
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.
 
#10 ·
Realtor1 said:
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.
 
#11 ·
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
 
#12 ·
ljklaiber said:
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
Paper filter above was meant to say AIR Filter, Castion means Cast Iron. Sorry bout my typing...lol
 
#13 ·
Lawrence said:
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.
 
#14 ·
becker_jr said:
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 .
A search for “tension bolt” 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...
 
#15 ·
ljklaiber said:
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.
 
#16 ·
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.
 
#17 ·
Anthony Cipriano said:
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.

Anthony Cipriano said:
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. :)
 
#18 ·
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.
 
#19 ·
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.
 
#21 ·
Gomeo001 said:
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.
 
#22 ·
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!
 
#23 ·
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.
 
#24 ·
RLLOVETT said:
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.
 
#25 ·
RLLOVETT said:
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.
 
#26 ·
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?
 
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