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346K views 93 replies 49 participants last post by  Ranger 
#1 ·
Hello, 93 ETC, some of you have been helpful with this car so far, thanks. Latest is that the car is still running hot. I had a thermostat replaced, even though the water was flowing through the overflow tank. It will run fine for 20 or 30 miles and then run hot. As I add more water it spills out bright green and eventually cools down. I brought it back to the shop, which did the thermostat because they had also said that it needed a radiator. They said that their inferred device had shown a difference in the radiator temps. I passed on the radiator replacement at that time. I figure that if the water is flowing and that could be seen, then it isn't the rad. The car ran hot once more after that so I returned the car to the mechanic. They called the next morning and said that the head gasket was blown. 20 hours to replace it and they couldn't do the work. 24 hours to replace the engine. They said that they could replace the engine for around $6500.

I am looking for a second opinion. Is there a way that I could easily tell if the head gasket is actually blown? It isn't the end of the world one way or another. It just seems strange to me that the car drives and runs great at all speeds and has power.

Any insights or suggestions are appreciated. Rad
 
#54 ·
The dealer you bought it from should be sued. They knew it was bad, guaranteed. Either way, Michigan law has a three day "cooldown" period law whichm no matter what you are told, is STILL on the books, and CANNOT be signed away, even if it is specified SOLD AS IS in the purchase contract. You are permitted to return the car without explanation to a private purchaser at the end of the period, with full refund, unless 500 miles have elapsed, whether or not you have started the title change procedure or not. If you buy from a dealer (car lot OR dealership) you have the right to return it if there is ANY cause to believe that mechanical problems were concealed.

You found out that the head gasket was blown? How? Did the car run itself out of coolant? Is it puking coolant out of the overflow line? If it did it within a day of yuo buying it, it had to have done it to the dealer as well. If they had to add coolant even once, that legally obligates them to check it further. It's a condition required of ALL dealers of all kinds, affiliated with an auto company or not.

It's just like the law that says a dealer in Michigan is prohibited from sell a car with a broken windshield (that's true, they cannot), while you or I as a private seller may do so if the buyer will buy it.

As for this water pump issue, the water pump in a 1992 is TOTALLY different.
 
#55 ·
I have a 1999 deville that's blowing white smoke out of the tailpipe. before this happened I had changed the thermostat because it was over heating ,then found a hole in the lower radiator hose and the radiator itself, so I replaced the thermostat,hose, and radiator and now have white smoke from tailpipe. Anyone have an idea what it could be? I'd appreciate the help.. thank you
 
#56 ·
White smoke, as in steam and/or burning coolant (do you have any coolant loss ?) is usually indicative of a failed head gasket in a Northstar. Not good.

Do some more research in here and then go to a NAPA dealer and pick up the exhaust gas test kit for the coolant surge tank. The kit uses a sample of the air/gas mixture above the coolant surface to give you a test result for exhaust gasses in the cooling system.
 
#57 ·
yes it's white like steam and coolant does get low,and I don't see any leaks. someone thought it may have been the water pump,but I was leaning more towards the head gasket(s) which I know can be a pain. Is the cylinder gaskets the same as head gaskets or different? I will try the test you mentioned before going any further. thanks
 
#59 ·
Oil runs at higher pressure(50-60psi at speed)than coolant so, oil will pump into & contaminate the cooling system first. At low rpm coolant can be higher than oil psi, then contaminating oil with coolant. If the engine is over heating the coolant temps can go over the normal 17psi. At Idle oil psi hot can be below 10psi. You will have oil floating in the reservoir with a bad head gasket. Cloudy crankcase oil is part of the same problem. Check the reservoir, check the crankcase, Thick white smoke out the exhaust is bad, and check your wallet if any of the above occurs.
 
#63 ·
I have a modified, no nitrous, 93 Eldorado running low 14's high 13's that had a similar problem. Note that some of these earlier Northstars also had insert problems that caused the head bolts to come loose, causing the cylinder head to separate from the engine block. In my case, it wasn't the head gasket or the insert issue. Also remember that the Northstar is a high performance V8 that runs fine at normal operating temps between 210 and 225 degrees. But the moment that you see a consistent overflow of coolant from the resevoir, you definately have a problem.

The following steps solved my problem as the root cause was air entering the cooling system, not from a head gasket or cylinder head sealing problem but from a faulty water pump seal. The factory water pump cover and respective seal are junk- the groove that contains the "o-ring" style seal is too small- not to mention, these covers easily crack near the 4 retaining bolts due to overtightening. Check for any white deposits near the water pump cover as this is a good indication you have a leak. What's important here is that a leak at this point will have the most immediate impact to increased coolant system overpressurization: It is here where the water pump sucks coolant from the radiator to the engine when the thermostat opens. A leaky seal at this point will act like a vacuum cleaner and suck a nice amount of engine compartment air along with coolant into the engine- I think we all know what air pockets in a cooling system can do.

Now the solution: Replace the OEM waterpump cover- the new cover has a larger groove and larger gasket or seal. This helps seal the cover better and prevents the "vacuum cleaner" effect I mentioned aboove. While your at it, replace the lower radiator hose & thermostat. Also, make sure you reuse the inner coil or purchase a new one for the lower hose- this is critical as the inner coil prevents a collapsing of the hose. Remember- the pump is sucking from the radiator to the block at this point. Without this internal coil the lower hose has a good chance on collasping on itself preventing proper coolant flow. Who knows, this may also be part of your problem as many people don't reuse the coil after replacing the lower hose- for some reason, almost all replacement hoses don't come with the inner coil support. Also, when attaching the new cover to the housing, put a washer on each bolt to help absorb some of the torque as you tighten them- this will help prevent cracking the cover.

Good Luck!!!
 
#66 ·
#71 ·
I agree..... it only buys you time (if it even works at all on a N*) but it gives you time to shop around for the right price and an honest tech to do the repair correctly.

I happened to have good results on a winter beater with Bar's. I bypassed the heater core for the first 500 miles, and then flushed the system, it never clogged anything except the head gasket


As far as "the miracle in a bottle" look at all the people who think synthetic oil will make their engine problom free....save the money on oil, and keep up "all" the other maintenance on your car. The cooling system is a biggy!

Just my 2 cents worth.......

Dale
 
#73 ·
It's not hard: It's impossible.

Head gasket repair liquids are designed to work under some pretty specific conditions, and one of those is that the head-block clamping/bolt pattern is good so the liquid can fill a void and harden. The Northstar problem is that the head bolts are slowly coming out of the block from compromised threads, so the head/block gasket space is never static: it is constantly increasing. It's sort of like trying to pour cement into the San Andreas fault: the fault is dynamic, expanding constantly, and there is not enough cement on (in) earth to seal it.
 
#74 ·
AC, you are describing my 97 STS. After a new thermostat, wp, gaskets at the heater pipes on the block, new radiator, lots of pressure testing, several gallons of antifreeze, and multiple use of every cuss word I've ever heard, we did a combustion test. This showed positive even though the car runs great and and no fluid mixing it was a blown head gasket. In my case new head gaskets were cost prohibitive so I used "Blue Devil". It says right on the bottle not to use in Northstars but on the advice of a couple caddy guys (and nothing really to lose) I gave it a try. 5000 miles later no overheating, no boiling over, no problems except a leak behind the front driver side wheel. I can't figure this out because as far as I know there is nothing to leak over there. Not telling you to use this product, only that I did and so far, so good. Good luck!
 
#76 · (Edited)
Go down to Discussions: Northstar Performance and open the sticky thread at the top of the page titled something like Headgasket Failure........ then click on the poll "view results" tab. You'll see that the 1998-1999 engines lead the group for failure.

Model makes no difference - it's the year of manufacture. Extensive changes in the 2000 year and after........
 
#79 ·
http://www.cadillac-doctor.com/

Best guy around if you are within, let's just say 500 miles give or take, to repair your N* motor. I gotta tell you, for $1500 he tears'em down and rebuilds them.

UNLIMITED mileage warranty for ONE FULL YEAR.

He ONLY does the N* motor and he's good at it. He did my 96 Eldo. Runs like a champ. Does great work. Upper N/E part of Ohio, but well worth the drive or have it delivered and picked up.

I bought my 96 Eldo from a 94 year old man...the state of Maryland took his d/l away because he couldn't pass the test anymore. His son was supposedly (and I use this term loosely) a mechanic. I took delivery of the car after asking more than adequate questions regarding the performace of the car...ANY issues...he stated there was NOTHING wrong with the car and it was in PERFECT running order. I drove it and bought it...I put tires, wipers, changed ALL the lights and bulbs, plugs & wires, had the oil changed, engine flushed, transmission flushed and drove off...so I spent another $1000 on the car after I took delivery. I noticed the engine was running over the "normal range" although it NEVER actually overheated...I started looking at Google and Cadillac Forum and the first thing I see (as I nearly threw up all over my brand new HP laptop) was this was usually a sign of a head gasket failure. The more I researched, the more I want to strangle this ass-wipe for not disclosing that the head gaskets have failed. Anyway...I had exhausted all avenues until I found this guy in Northeast Ohio...

Solid 10 on the scale...great guy...I'll take my Eldorado to him ANY DAY!!!
 
#85 ·
I like this throwing up portion. I feel about the same right now.

I sold my Harley last week and got this 97 Sts. As I always wanted one.
I checked all the telltale signs oil coolant. Exhaust. Looked great. It runs like snot and purrs like a kitten.
I wish OH wasn't so far. Cuz my gut tells me I got suckered in.
 
#80 ·
That is a great price, but in reading his repair procedure he does not mention using any inserts or studs.

"We then drill out every head bolt hole, on both banks, both sides, not just the side that is bad as a few other repair shops do. We then tap each hole using precision taps, not just your local auto parts store taps. After we tap each hole and it has been thoroughly cleaned with a cleaning agent, we then insert a bore scope and look at each of the threads to insure they are threaded correctly. After this is done, we remove the tape and clean all the carbon and varnish out of your piston cylinders. We then install new dowel pins and install new felpro head gaskets, then the heads along with new felpro head bolts."
 
#81 ·
I ran across this on ebay and its the same company referenced above. studs for 300.00 more

NOTE" PLEASE DO NOT HIT THE BUY IT NOW, JUST EMAIL ME OR CALL ME. THANKS 330-507-9248 WE ARE NOW OFFERING REPAIRS USING STUDS FOR ONLY $300.00 MORE! All Cadillac Northstar Head gaskets, 1993 thru 2004 repaired, with warranty for $1500.00 this includes all parts and labor We at Davis Auto repair, all we do is work on and repair the wonderful Cadillac Northstar engines as well as the northstar engines in the Oldsmobile Aurora. We have several years experience with these engines. We have repaired the head gasket on over 200 of these engines to date.
 
#82 ·
I own a 99 Deville and love that car, but have been fighting a overheating problem for over a year. Runs great but dumps coolant out of the resivor and overheats. I taped a bottle onto the overflowtube to prove it to myself because i could never see any water on grownd, white smoke, air bubbles, water/oil mixing . Just losing coolant. Now all this started when I drained the coolant and put in the new antifreeze, I did try the fix in a bottle and it worked great for a while. Then I read a tag on top of the rad that said to add these pellets from GM if the system was ever drained , that also worked great.... for a while. Now the problem has returned and I am pretty sure it is a HG problem but will try some of the test I've read here to confirm. I may have not put pellets in properly (did not put them in bottom rad hose as directed but in resivor...easier to do) But with the costs of the repairs i have read about I think I will try the temp "fix in a bottle" so I can afford to put gas in the car. I was wondering weather why no one else mentioned the coolant pellets from the dealer, mabey they would rather do all those other tests and repairs than sell you the $5.00 pellets that are recommended.
 
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