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99 STS Head Gasket Failure AGAIN after 18 months


Captain Rob

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After $3K and 18 months and only 10K miles since getting my head gaskets replaced and time serted she is over heating again. The mechanic that first fixed it looked at it yesterday told me the head gasket went bad due to the catalytic converter being plugged which Is something I never heard of or never witnessed any signs of that being an issues. The mechanic only gave me a 12 month warranty and is not going to anything about it except charge me another 2K for the fix.

Wouldn't a clogged converter trip off a warning on the on-board dyno?

Is there anyway to check that it was properly done without ripping the car apart?

Does anyone want to buy a 99 STS with 114K on it?

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I would think that a clogged CAT would result in performance problems both that you feel and that set a code, so he is mistaken and making an excuse.

How were your temps up till that point?

How sure are you that he timeserted the engine to begin with?

Had he done timeserts before?

Its too late now, but did he determine that the block COULD be timeserted, was the material good?

Did he use the timesert kit?, jig, drill and tap set?

He must use big serts now

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Well, you could always start by checking the purge line is free flowing...likely it is but doesn't hurt to check the easier things first,water pump tensioner/belt action,fan operation. Does it consistently overheat?

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When I originally researched the problem and discussed it with the mechanic back 18 months ago, he knew what needed to be done, he said that he brings in a guy that specializes in the Northstars time sert issues.

I just ran the codes and nothing is current, the car runs like a bat out of hell, so there is no performance issues.

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When I originally researched the problem and discussed it with the mechanic back 18 months ago, he knew what needed to be done, he said that he brings in a guy that specializes in the Northstars time sert issues.

I just ran the codes and nothing is current, the car runs like a bat out of hell, so there is no performance issues.

This tells me there is NO WAY you have a clogged cat. I had a MILDLY clogged cat a few months back, and my car felt as though it was towing a house when I tried to accelerate. It had NO GUTS AT ALL! I've never heard of a clogged cat causing HG failure either. I imagine it COULD happen, but it would have to be really bad, and be that way for quite some time.

Check your coolant for combustion gasses to verify or rule out the HG. They sell the DIY kits at several auto parts stores. If you need to bring it to a shop to have it tested, I would advise taking it somewhere else.

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That is good advice Carla, I agree with what you are saying and that was what I was trying to get at in my post.

Something smells here, 18 months later?, it might have lasted that long if they used the OEM bolts without timeserting the block, so this is ODD that it could fail so quickly with a good timeserting job by an experienced mechanic, that is why I asked about the mechanics experience, we have seen DEALERS do timeserting wrong... but Rob, quickly responded with

he knew what needed to be done, he said that he brings in a guy that specializes in the Northstars time sert issues

So Rob appears be confident that all is fine, even though has asks "am I getting screwed"................. I am not confident that all is fine however, time is money, mechanics take shortcuts, if the block had poor aluminum from overheating, its NOT likely the timeserter would have raised a red flag to KILL the block, he wouldn't have gotten paid. A job that is sub'd out to a third party, makes me nervous. It would take a VERY honest mechanic to do the right thing if the rear bank's aluminum alloy material turned to dust from heat. If that happened, it would be like putting the timesert into BUTTER, and it would pull out just like the bolt did. I had extensive discussions with the timesert guys about that.

And dont think that I am being PICKY here, I spoke to two engine rebuilders and many NS blocks get REJECTED for this reason.

The other thing is, its important to be knowledgable about this job in order to ask the right questions BEFORE the job is done. At this point the answers you get will be cover answers telling you want you want to hear. Or they will deflect the problem and say it was caused by a CAT so you can't sue them in a small claims court for non performance. As you said, a CAT saps the engine of power, my monte carlo had NO power with a bad cat., so this guy is full of it

KHE bought a Seville and found that the timesert job was done wrong and the serts pulled, so it is possible.

Mechanics are about collecting on a job, I took my 91 Seville to a tranny shop RECOMMENDED by the local caddy dealer and they TOTALLY screwed up my car, to the point where I had to come back immediately because the brake backing plate was smashed up against the rotor, the oil pressure light came on in 10 miles as the cooler lines were leaking and they pinched a wire between the engine and transmission and in 6 months I burned out a fusible link and knocked out my cooling fans and AC compressor. Shocking considering that I told the shop owner that I would do it myself but didnt have the time and that I was a fanatic! They never test drove the car after they installed the tranny. Just collect $2200. He had thank you letters all over his walls, but it would be doubtful that he would have put my YOU SUCK letter on his wall, so I didn't bother! I went back to the caddy dealer and told them that the shop sucked and provided them with a list of problems upon delivery. They were going to stop recommending them as a result of my experience, so I accomplished the desired result.

Many mechanics are SLAM BANG mechanics and they dont worry about details.

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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Thanks for the response so far, this is what the mechanic responded with:

It was both head gaskets. When we drove the car it had a loss of power the warmer the temperature and stunk as a plugged catalytic conveter does so we took the car to the muffler shop around the corner and they verified that it is plugged.

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First, as Carla says, I would not go back to this guy. Since he isn't backing his work and the warranty is expired, you have no reason to take the car back to him.

Clogged cats don't stink. Bad fuel or engine problems can cause exhaust odors, and many of them, such as the rotten-eggs smell from cheap gas, won't come from a car without a cat.

Quite possibly your car does not have more head gasket problems. There are a lot of reasons a car can overheat. I would start by having the coolant checked for combustion by-products, checking the return hose to the coolant tank from the water pump, and the water pump belt.

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-- 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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Thanks for the response so far, this is what the mechanic responded with:

It was both head gaskets. When we drove the car it had a loss of power the warmer the temperature and stunk as a plugged catalytic conveter does so we took the car to the muffler shop around the corner and they verified that it is plugged.

If the cat is "PLUGGED"...the car won't hardly get out of it's own way...PERIOD...END OF STORY.

I have been down THAT ol' road myself.

If it still has plenty of POWER...the cat IS NOT PLUGGED.

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What burns me, is that I love this car, my intent was to fix everything wrong with and use it as a driver. The head gasket job was huge deal for me, which lead me down the path to replace the struts, shocks, complete brakes all around, alternator, the 17 inch STS rims and tires and much more. I was almost done with this project and thought I had another 100K left or more.. :(

So what are my options or what would you do?

Look for a new car and be done with this project?

Spend another 2K to get it fixed? What kills me, I have over 5K into this car over the last 22 months.

What if I find the head gasket/time sert job was done incorrectly, do I have a case in court?

Bummed in MI, its cold up here.

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Thanks for the response so far, this is what the mechanic responded with:

It was both head gaskets. When we drove the car it had a loss of power the warmer the temperature and stunk as a plugged catalytic conveter does so we took the car to the muffler shop around the corner and they verified that it is plugged.

If the cat is "PLUGGED"...the car won't hardly get out of it's own way...PERIOD...END OF STORY.

I have been down THAT ol' road myself.

If it still has plenty of POWER...the cat IS NOT PLUGGED.

The car runs like a top actually, not that I beat on it, but it gets about a foot of rubber going from first to second gear. Not sure if that's normal, but it does run nice.

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What burns me, is that I love this car, my intent was to fix everything wrong with and use it as a driver. The head gasket job was huge deal for me, which lead me down the path to replace the struts, shocks, complete brakes all around, alternator, the 17 inch STS rims and tires and much more. I was almost done with this project and thought I had another 100K left or more.. :(

So what are my options or what would you do?

Look for a new car and be done with this project?

Spend another 2K to get it fixed? What kills me, I have over 5K into this car over the last 22 months.

What if I find the head gasket/time sert job was done incorrectly, do I have a case in court?

Bummed in MI, its cold up here.

You don't even "KNOW" yet that it needs fixing.

All you actually know is from the so called mechanic that don't stand behind his work.

I don't remember if you have pulled the codes or not...

If not..pull them and post them here.

Then....The "FIRST" thing to do is have a combustion gas test done.

Either buy a kit from NAPA or take it to a reputable radiator shop and have it done.

Then go from there...you can't make "ANY" decision till you "KNOW" what is actually wrong with it.

It may be something as simple as the purge line stopped up...which will cost "ZERO" dollars to fix.

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Thanks for the response so far, this is what the mechanic responded with:

It was both head gaskets. When we drove the car it had a loss of power the warmer the temperature and stunk as a plugged catalytic conveter does so we took the car to the muffler shop around the corner and they verified that it is plugged.

If the cat is "PLUGGED"...the car won't hardly get out of it's own way...PERIOD...END OF STORY.

I have been down THAT ol' road myself.

If it still has plenty of POWER...the cat IS NOT PLUGGED.

The car runs like a top actually, not that I beat on it, but it gets about a foot of rubber going from first to second gear. Not sure if that's normal, but it does run nice.

Then you DO NOT have a stopped up cat.

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Thanks for the response so far, this is what the mechanic responded with:

It was both head gaskets. When we drove the car it had a loss of power the warmer the temperature and stunk as a plugged catalytic conveter does so we took the car to the muffler shop around the corner and they verified that it is plugged.

If the cat is "PLUGGED"...the car won't hardly get out of it's own way...PERIOD...END OF STORY.

I have been down THAT ol' road myself.

If it still has plenty of POWER...the cat IS NOT PLUGGED.

The car runs like a top actually, not that I beat on it, but it gets about a foot of rubber going from first to second gear. Not sure if that's normal, but it does run nice.

Then you DO NOT have a stopped up cat.

I know, it runs great, no issues.

I replaced the thermostat, I checked the purge line, I checked the serpentine belt. The radiator is fine.

At times I can smell antifreeze while driving or shutting down the car.

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I would go to a radiator shop so that you have a third parties opinion in writing, I would NOT do this test myself

I would ask to speak to the timesert mechanic and I would ask him how he timeserted the engine. Set him up with a recording on the line and ask him this, Did he, did he drill the holes by hand then use the inserts?, then get him to talk, how did he do the timesert job in detail, then ask, what was the aluminum material like? See how he reacts to that question, see what he says. The aluminum can be ruined, dont let on that you know that, query him and let him talk... Most mechanics are know it alls and will be head strong. He will probably dump on the Northstar at some point.

Get him to talk

A detailed analysis needs to be done at this point on disassembly. I would DEFINATELY want to see if the block was in fact timeserted, as of right now, you have NO idea as to whether or not it was. You dont know if he ONLY timeserted obviously bad bolt holes and torqued the others. if that happened, you have a big suit on your hands

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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You say you smell coolant when you are driving. Have you ruled out a leaking heater core?

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Maybe I missed it, but I don't recall your actual symptoms. A clogged CAT, and it runs like that? Give me a break. You are being fed a line. A coolant smell indicates an external leak and that is not a HG. I'd follow BBF's advice and talk to the guy that did the Timeserts. Get a second opinion from a REAL mechanic. I'm not yet convinced that you have another HG failure either.

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If you smell coolant from the drivers seat then you have a coolant leak under the hood or in the heater core.

CTS-V_LateralGs_6-2018_tiny.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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My water pump cover had a pinhole leak in it and I could sometimes smell coolant when driving, so it doesn't take much for you to able to smell it. It could be a minuscule leak.

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  • 3 weeks later...

OK, just had my 3 opinion and they all point towards the head gasket.

After all the work done, would you:

Sell the car as is? What would you ask based on my passed description.

I have quote for 2250.00, which is redoing the time serts that already have been done. He would be giving me a 6 month warranty plus take care of certain gaskets that need to be replaced so the car will not leak oil.

What would you do?

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At $2250 this guy is working for nothing.

What can you tell us about the mechanic? How many has he done? Why is he redoing ALL the serts?, that is not necessary

Did he tell you what cylinders this is affecting?

As is, if the purchaser is smart, he should offer you the current value of the car based on condition and mileage LESS about $3500 for a total timesert job, LESS about $1000 due to the fact that it has FAILED, and there is a huge UNKNOWN

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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How was the diagnosis performed? Cylinder pressure test? Combustion byproduct test?

Earlier, you reported a coolant smell which is an external leak. Have you fixed the leak?

I'm not convinced that the headgaskets are shot yet but to answer your question, IF the headgaskets are shot, the car is worth $1500.00 as is.

The second repair will need to use Bigserts and the original Timeserts will need to be drilled out.

The repair or sell decision would depend on the condition and mileage of the car. Would you be better off putting the $2250.00 towards an '03 or '04 STS? Those are the kinds of questions you need to ask yourself.

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

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