ctmccloskey

Northstar head gaskets

8 posts in this topic

I have. 1994 DeVille Concours and it recently turned 132,000 miles. I heard a clicking coming from the Idle air Control Valve after replacing it. I couldn't stop it so I decided to support my local dealer and dropped it off.

They fixed the IAC valve and proceeded to flush my power steering system, this is where the trouble begins.

I get a call from the dealer and the service advisor tells me he has bad news. "The car seriously overheated he tells me when the car is left idling for a while. I know you won't like this but your car suffered serious damage and may have warped one or both of the cylinder heads when your head gasket blew." He then asks for permission to start disassembling my engine so he can give me an estimate on the fix. I told him "no" , the car is not worth several thousands of dollars worth of work.

In the beginning I had mentioned that the car seemed to be running hotter than normal, and what is considered normal? They did not test for carbon monoxide test until after the mechanic had "severely overheated your car". The dealer has decided not to charge me for the diagnostics and the power steering flush. My bill is about $700, why would they be so eager to eat that?

The dealer tells me that the car "should" make it home and might be good for A year or two. They said that the blown head gasket isn't bad enough to keep me from driving the car. He suggested that I not drive through any deserts.. In my world a head gasket is either Blown or Not Blown, what is a blown engine to a dealer?

1.What do I do now?

2.Can a head gasket blow allowing combustion gases into the anti-freeze without oil in the antifreeze or antifreeze in the combustion chamber?

3. How bad is this problem? The dealer said I was lucky to go 132k miles without other problems.

4. How do you protect yourself from dealer mistakes?

5. Do I hire a lawyer or what?

6. Is there any fix for this problem?

7. I am a pretty good mechanic and have replaced heads before. Is there a particular place where these engines blow their head gaskets?

8. If I reduce the engine operating temperature by using a good water wetter and maybe a lower thermostat like a 185 and really good coolant. I would also use lower settings for the fan relay driver.

9. Should I try to fix the head gaskets or will they blow again?

Any thought or ideas are absolutely welcome.

I remember my original dealer telling me that the "Northstar" engines were designed to run hundreds of thousands of miles. As an engineer I believed the baloney as the engine looked good as was strong enough to push my 1994 Seville STS to a 14 second quarter mile. What when wrong? Why doesn't Cadillac protect their image? I bought the STS first and the DeVille second, they are both Northstars

What do I do? Help me please!

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Sorry you had this adventure with your dealer.

First do a test for combustion gases in the coolant and determine if the head gaskets are leaking. Then you can make fact based decisions on how to proceed.


Bruce

2016 Cadillac ATS-V gray/black; 2013 Cadillac ATS 2L Turbo Premium (Wife's)

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Welcome to caddyinfo.

I will do my best to try to answer a few.

Yes a blown headgasket can allow combustion gases only to leak. It is the most common beginning stage. When the car is running it blows exhaust gases into the cooling system super heating the coolant and causing it to purge from the tank. Also when the car is off and cooling it can allow coolant to push into the exhaust and will be burnt off on startup.

Given the age of the vehicle anything is possible and nothing lasts forever.

Unfortunately having all aluminum engine can mean pulled head bolts over time which is likely your problem.

It is unfortunate that it happened at the dealer but regardless it happened. They probably had it running and left it alone, then it was too late..

For the record I never let my cars idle. Either drive it or shut it off. I dont care for running them parked. .

I wish you the best of luck. Please keep us posted


GM FAN FOREVER

Nice, clean, luxury= fine automobile

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With any aluminum block or head or intake manifold that has water running through it - which is to say just about any car nowadays, you *must* keep the coolant fresh or you will have serious problems. With green coolant, that means flushing and changing it every two years or sooner, and with red or orange "long life" coolant that means about every four years.


CTS-V_Dashboard.jpg
-- Click Here for CaddyInfo page on "How To" Read Your OBD Codes
-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data
-- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC
Yes, I was Jims_97_ETC before I changed cars.

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I have. 1994 DeVille Concours and it recently turned 132,000 miles. I heard a clicking coming from the Idle air Control Valve after replacing it. I couldn't stop it so I decided to support my local dealer and dropped it off.

They fixed the IAC valve and proceeded to flush my power steering system, this is where the trouble begins.

I get a call from the dealer and the service advisor tells me he has bad news. "The car seriously overheated he tells me when the car is left idling for a while. I know you won't like this but your car suffered serious damage and may have warped one or both of the cylinder heads when your head gasket blew." He then asks for permission to start disassembling my engine so he can give me an estimate on the fix. I told him "no" , the car is not worth several thousands of dollars worth of work.

In the beginning I had mentioned that the car seemed to be running hotter than normal, and what is considered normal? They did not test for carbon monoxide test until after the mechanic had "severely overheated your car". The dealer has decided not to charge me for the diagnostics and the power steering flush. My bill is about $700, why would they be so eager to eat that?

The dealer tells me that the car "should" make it home and might be good for A year or two. They said that the blown head gasket isn't bad enough to keep me from driving the car. He suggested that I not drive through any deserts.. In my world a head gasket is either Blown or Not Blown, what is a blown engine to a dealer?

1.What do I do now?

2.Can a head gasket blow allowing combustion gases into the anti-freeze without oil in the antifreeze or antifreeze in the combustion chamber?

3. How bad is this problem? The dealer said I was lucky to go 132k miles without other problems.

4. How do you protect yourself from dealer mistakes?

5. Do I hire a lawyer or what?

6. Is there any fix for this problem?

7. I am a pretty good mechanic and have replaced heads before. Is there a particular place where these engines blow their head gaskets?

8. If I reduce the engine operating temperature by using a good water wetter and maybe a lower thermostat like a 185 and really good coolant. I would also use lower settings for the fan relay driver.

9. Should I try to fix the head gaskets or will they blow again?

Any thought or ideas are absolutely welcome.

I remember my original dealer telling me that the "Northstar" engines were designed to run hundreds of thousands of miles. As an engineer I believed the baloney as the engine looked good as was strong enough to push my 1994 Seville STS to a 14 second quarter mile. What when wrong? Why doesn't Cadillac protect their image? I bought the STS first and the DeVille second, they are both Northstars

What do I do? Help me please!

The '94 Northstar does not have an idle air control - it has an idle speed control motor. Most likely, the closed throttle switch was not making proper contact so the system was "hunting" for the correct throttle angle in preparation for the next restart. There is no need for a power steering "flush" - that is just a money maker for the dealerships. Nowhere in the owner's manual maintenance schedure is a power steering flush recommended or even mentioned. Maybe the dealer mechanic wanted to buy your car at a cheap price? It is highly unlikely the cylinder heads warped... I purchased a '97 Seveville STS that needed headgaskets and was overheating back in 2006 at a bargain - when I had the heads off and put them on a granite surface plate, they were not even .005" out of perfectly flat.

Some anwers to your other questions:

  1. Check the purge line to the surge tank to make sure it is flowing. Borrow the cooling system exhaust tester from Autozone and test the coolant for exhaust yourself. You will know in a few minutes if the head gaskets are bad.
  2. Yes - In the early stages. When it is in the advance stages, it will dump coolant into the oil.
  3. The dealer is full of crap... I had 150,000 on a Seville SLS and it did not have head gasket issues. A neighbor had a 1998 Deville with 240,000 miles on it that never had an issue.
  4. I protect myself by not taking my vehicles to dealerships after the warranty runs out.
  5. Are you serious??? What would that accomplish on a 20 year old car with 132,000 miles on it other than lightening your wallet further? If any lawyer was dumb enough to take it to court, he'd be laughed out of the courtroom in short order.
  6. Yes - if the head gaskets are blown, the engine needs to come out and the head bolt holes are machined to accept Timeserts. Timeserts are the only factory authorized repair. THe engine will be stronger than new once the repair is completed properly. While the engine is out, it's a good idea to re-seal the lower crankcase half and replace the oil manifold plate. Using the GM Engine sealant (there is NO aftermarket substitute), the engine will not leak a drop again.
  7. No single place - some are in the rear bank (1-3-5-7) but we've seen them blown on the front bank as well. More than likely, a head bolt(s) has pulled if there is actually exhaust getting into the coolant.
  8. No need for any additives to the coolant - snake oil in a bottle will not fix a breached headgasket. You need the 195 degree thermostat - with a lower thermostat, the engine will not warm up enough to boil any condensate out of the oil and that will do damage to the engine.
  9. If the car is in good shape and you like it, it is worth more to you than the book value. A repaired engine, if done properly, will be fixed and unlikely to pull a bolt again. If you do the work yourself, expect to spend about $1500 - $1600 in parts and about a week to do the job.

Remember, your car is 20 years old.... Cadillac makes great cars but not lifetime cars... Nothing lasts forever - sooner or later, everything mechanical will need maintenance at some point.

rockfangd likes this

Kevin
'93 Fleetwood Brougham
'05 Deville
'04 Deville
2013 Silverado Z71

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wow you nailed everything.

blunt but right to the point


GM FAN FOREVER

Nice, clean, luxury= fine automobile

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Is this the place where I can ask questions about my 01 Deville overheating?

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Yes, but you are better off starting a new topic. The original post and KHE's reply is a good education about overheating and blown head gaskets. The first thing to do is to check for a clogged bypass, make sure that you have 50-50 antifreeze in the coolant, etc. If so, then check for combustion by-products in the oil.


CTS-V_Dashboard.jpg
-- Click Here for CaddyInfo page on "How To" Read Your OBD Codes
-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data
-- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC
Yes, I was Jims_97_ETC before I changed cars.

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