1996 STS with 47,000 miles overheating!!!

2904 Views 16 Replies 7 Participants Last post by DBA-One, Aug 22, 2007

QueensLacMan

Discussion Starter · May 31, 2007

I have this problem I'm hoping Ranger or someone can help me out with. I just bought a 1996 STS with 47,000 miles (original) for $4350. It was owned by an old man who barely drove it. One owner. He showed me all the paperwork. He serviced the car at the dealership every two months for the first five years. You'd think problems would be far and few.

Anyhow, the car is overheating on me. I had to pull over today and sit for 20 minutes until the temp went down. Coolant loss was present.

Less than two years ago, the original owner had overheating problems. He saw a mechanic and had everything replaced. New thermostat, new radiator, etc. It was like $900. He gave me the receipts.

So I doubt it's one of those things. The radiator cap seems like it's the right one. The purge line I'm pretty sure is clear (I poured in too much coolant and out it went through the line).

I poured a full container of coolant (orange - Dexcool) about three weeks ago and today I got a message telling me to check coolant levels. I went to gas station and bought what was available (it was green, but it said it could go with any color - it was 50/50 etc.) and poured 90 percent of the container in.

How did I lose that coolant? I didn't see it come onto the ground. It's as if it evaporated somewhere.

I'd drive on the highway and the engine will get hot. I'll pull over for five minutes and then resume driving, and the car will be fine for over an hour. This happened to me once or twice. Only today did it get to the point where I was really concerned (I had to keep pulling over just to go a short distance).

What could the problem be? What's my next step?

I'm planning on going to the mechanic tomorrow (good luck finding one who knows about Caddys) and telling him to do a cylinder pressure test.

Another thing, and I don't know if this is related, but when I first took the car in to the shop to be checked out, my mechanic told me I needed a tune-up. He removed the sparkplugs and showed me that they were covered in oil. Should oil be getting on the sparkplugs? Anyhow, I did the tune-up.

Could this car have a head gasket issue at 47,000 miles? Could not driving the car often and hard enough do just as much damage as overusing it?

Any info would be tremendously appreciated. You guys are great.

Thanks. I hope you are all well.

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CadillacSTS42005

· #2 · May 31, 2007

yes it could have the issue
how the heck did you cut that deal?

Ranger

· #3 · May 31, 2007

The purge line I'm pretty sure is clear (I poured in too much coolant and out it went through the line).

Sounds like you are talking about the overflow line. The purge line runs from the water pump housing to the surge tank. Pull it loose at the tank and see if you have flow at idle (preferably cold so as not to burn yourself).

How did I lose that coolant? I didn't see it come onto the ground. It's as if it evaporated somewhere.

Worst case scenario is that it is a head gasket and is going out the tail pipe.

What could the problem be? What's my next step?

I'd say next step is a cylinder pressure test. If that turns out OK, do a cooling system pressure test. It is possible that there is a small external leak that is evaporating before it drips. Radiator side tanks are a common culprit.

Should oil be getting on the sparkplugs?

No, but it is not uncommon. There are "O" rings in the cam cover that seal the plug wells. They can leak over time. Not a big deal.

Could this car have a head gasket issue at 47,000 miles? Could not driving the car often and hard enough do just as much damage as overusing it?

Remember, it is 11 yrs. old. Time plays a role as much as miles. Whether not driving it much would play a role, I am not really sure.

Best of luck and let us know how the tests come out.

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QueensLacMan

Discussion Starter · #4 · May 31, 2007

Will do. Thanks a ton, Ranger.

QueensLacMan

Discussion Starter · #5 · May 31, 2007

About how I swung that deal, I guess I just got lucky. I wasn't even in the market for a new car. I check the cars on Craig's List often, and there it was, a steal (well, let's see how these tests come back). The owner was like 75 years old. He had the car garaged. The leather isn't even broken in. It smells new. I'm sure he could have gotten $7500 for it. He said he didn't care about the money, and that he just wanted it off of his hands.

Hey... if these tests come back OK, and the car holds up, I made off like a bandit. We'll see... sometimes things are too good to be true.

Let you guys know how it turns out.

Cheers.

Ranger

· #6 · May 31, 2007

Even if the tests come back negative, you got it cheap enough to have it repaired, still be in the ball park and have it last for a long time.

Playdrv4me

· #7 · May 31, 2007

Ranger said:
Even if the tests come back negative, you got it cheap enough to have it repaired, still be in the ball park and have it last for a long time.

I agree.. theres rarely such a thing as a "free lunch". The old man knew the headgaskets were going which is why he let the car go so cheap, especially if he had already thrown 900.00 at the problem before. Once you repair it youll be in it for what its worth, but youll have a nice low mileage car that wont have headgasket problems again.

QueensLacMan

Discussion Starter · #8 · Jun 1, 2007

Going to the mechanic tomorrow. Any idea how much a cylinder pressure testand/or cooling system pressure test should cost? I live in New York City -dunno if that makes a difference. Thanks. Wish me luck.

Playdrv4me

· #9 · Jun 1, 2007

QueensLacMan said:
Going to the mechanic tomorrow. Any idea how much a cylinder pressure testand/or cooling system pressure test should cost? I live in New York City -dunno if that makes a difference. Thanks. Wish me luck.

Not much... try a Radiator shop... they usually do it for very little.

Good luck.

QueensLacMan

Discussion Starter · #10 · Jun 1, 2007

I'm not a happy camper today. I took the car to the mechanic and explained to him how the temperature in the car would volley back and forth as I went up and descended hills; accelerated on the freeways; sat in traffic, etc. It wouldn't just slightly increase and decrease. It would get really hot and then cool down with a change (turn off AC, decrease speed, etc). My mechanic said this kind of fluctuation is a sign of bad head gaskets.

He did the pressure test to check for leaks and said there were none. However, coolant was being lost somewhere.

We were about to do the cylinder pressure test when my mechanic inspected the spark plugs and told me they were corroded by anti-freeze. He showed them to me and they were white as if they had been burned by a chemical. Whether or not they were, I have no idea. The plugs are all new for I had a tune-up done just three weeks ago. The car wasn't overheating then. No codes. Everything seemed fine. I don't think there was anything I could do prior to buying the car to find out it had a gasket issue. A part of me is still hoping it's not a gasket issue.

This information about the white spark plugs - is that enough to confirm the gaskets are bad? Should I still have the cylinder pressure test done?

There's no white smoke. There's no sweet smell. There's no false boiling or bubbling in the coolant tank. But if I have the AC on and I'm driving it gets hot, and coolant comes out of the overflow. When I have the AC on and I'm not driving, everything is fine. If I'm driving without the AC on, it seems fine.

I've had this car for about a month and it's been good for the most part. Even when I test drove it, it was a hot day and I had the AC on and I drove it for at least 15 minutes on the freeway, etc.- and everything was fine. I've driven it to and from work with the AC on and everything was fine. Could it all just unfold so damn quickly?

My mechanics aren't bad but I don't think they know Cadillacs the way some of you guys on here do. I'm hoping you can tell me something else rather than head gaskets caused the spark plugs to turn white.

Do you think this is even worth exploring more? Should I just try to sell the car for whatever I can get for it? Would someone buy it for $3000 knowing it has a blown head gasket? Or would I have to go about selling the car without disclosing the problem in order to get back some of my money? I don't want to do that. I'm not that kind of person.

Educate me, please. Thanks again.

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Cad tech

· #11 · Jun 1, 2007

You need a block check done...What this does is test the amount of CO2 in the coolant system..If there is CO2 evident in the block check you need head gaskets and inserts done..

QueensLacMan

Discussion Starter · #12 · Jun 1, 2007

And if there's no CO2 present... does this rule out head gasket failure?

QueensLacMan

Discussion Starter · #13 · Jun 1, 2007

Also... and I don't know if this is connected or not... but I've been getting a code and message related to emissions. PO174. Is this related to the gaskets?

This SUCKS.

Ranger

· #14 · Jun 2, 2007

P0174 - Fuel Trim System Lean Bank 2

That could be a vacuum leak. Not sure if a head gasket would cause that or not.

QueensLacMan

Discussion Starter · #15 · Jun 2, 2007 (Edited)

Saw your reply on the other post. Thanks again. I'll let you know how this comes out.

Nicksterwin

· #16 · Aug 22, 2007

I'll buy it knowing the problem for $3,000. But live in Houston, TX

DBA-One

· #17 · Aug 22, 2007

So you had new plugs done just before this started? Did I read that right? Possibly cracked heads from the being too tight?

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