View Full Version : Is head gasket a common problem with sts

03-03-06, 02:15 AM
It seems to me that this headgasket problem is pretty common with Seville STSs, or is it?
Well, here is my story...
I got my '99 Seville STS a year and a half ago with about 150K miles on it. Now I have 163K on it and I absolutely love it. It is very powerful, luxuries, and sharp looking. However, now I am debating to either keep it or not?
I would smell burnt coolant smell coming through the vents. I had it checked at the Cadillac dealer and they said headgasket(s) is/are cracked, and they said it would be about $5000 for a new engine w/labor. Well I told them NO. But before I even got there to pick it up, their sales person called me and started talking about trade ins. At that point, it felt fishy. So I asked about it to my friends, one who knows much more than I do said it may be radiator or water pump. After both got replaced, the smell and the coolant loss got dramatically got less. I would smell it only if I accelerate fast, or when I am sitting at a stop light. But it is enough to freak me out, cause I still owe money on it. Enough to buy me a less feature but much lower miles car. I tried doing the false boiling test today, and it did boil over, but first I drove with the cap on to warm it up (I live in Mn, so it doesn't warm up at all when it just sits there ), and then made it rest a while with engine turned off, then I removed the cap and started the car again. For a while the coolant in the overflow tank just moved around, and I saw quite a bit of brown dirt looking particles in there... after that out of a sudden it just bubbled up and it overflowed pretty badly... Trying to close the cap to stop the flow, I had unwanted contact with the coolant but it didn't burn my hand...???
Did I do it right? Was that "false boiling"?
I also have bad suspensions on it, and transmission makes a big hit when I put it in D. Not all the time, but mostly. So here is my story, and I desperatly need help...
The biggest problem is that I am very attached to it, but I am scared that I may be making payments on a car that has a big chance to brake. There is no way I can spend 3-4K to fix it while I am still paying for it.
Thanks already for even reading my crazy story.

03-03-06, 03:00 AM
First off, I smell a rat with the service depatment and the sales call. Secondly, a bad head gasket will usually burn the coolant and you will not smell it through the vents. You may at the tail pipe and you would likely be over heating. Thirdly, when you run the engine hot with the cap off, you lower the boiling point and it WILL over flow. If you are smelling coolant, I would suspect an external leak, water pump cover gasket is a common cause. Get a second opinion.

03-03-06, 08:56 AM
look for air bubbles from the bottom hose going to the overflow tank. air bubbles = head gasket redo

Rob S
03-03-06, 10:09 AM
If you smell coolant in the vents, could be the Heater core. I agree with Ranger about your dealer, smells fishy.

03-03-06, 10:40 AM
If you smell coolant in the vents, could be the Heater core.


and if you're not overheating, you're probably fine headgasket wise.

03-03-06, 02:14 PM
Thanks a lot everybody, you are great.
I will check to see if there is any burnt coolant smell coming from the exhaust.
Generally, my car doesn't even get fully warmed up (needle doesn't get to the middle part in the temp gauge) when I am driving long distances... IS that normal?? But then again it's quite cold here in Minnesota. I had the water pump and the radiator replaced mid-fall so the car hasn't been in warm weather yet to see if it's gonna overheat. Otherwise, when I am in traffic it fully warms up, but does not overheat. My coolant loss is about a quarter in 3000 miles, just like oil loss.
As far as looking for bubbles go, do I just start it with coolant overflow cap off, and idle it? Do I wait until the engine warms up, or will bubbling occur instantly?
Would there be a power loss if head gasket was blown or cracked? Cause I don't seem to have any power loss - although I don't know how a newer one would perform-. But all I know is that I had a firebird formula before the STS, and it (even with many miles) is not much slower than that.
thanks again.

03-03-06, 02:47 PM
As for the bubbles, if your coolant tank is churning while the coolant and engine are cold theres a sign, if you have tremendous clouds of vapor while sitting at a redlight that billow all around you like my car does, then that is a sign, if you have a lack of compression while the engine is cold and a rough start and rough running before standard operating temp is reached then theres a sign,

these are all signs that my car exhibits right now. My head job starts this sunday. Sounds like you have some obscure other problems to me.

Even if you get a small stream of bubbles coming through the surge tank it is something to look for, when your water is boiling and you open the cap and pressure drops or the water was very hot and the cap opens and the pressure drops then a surge out the top of overflow is normal. This is not the conditional bubbles your looking for. Your looking for any other backpressure or air coming through when the boiling point condition has not yet been met.

Hope that helps,lol

03-03-06, 02:48 PM
And another thing, the title of your thread is shows a jaded way of looking at your problem, dont compare this issue so much to the STS's as you should look more towards the NorthStar 4.6L engine you have. My Eldorado and a host of others have the exact same engine.


03-03-06, 04:48 PM
As far as looking for bubbles go, do I just start it with coolant overflow cap off, and idle it? Do I wait until the engine warms up, or will bubbling occur instantly?
Would there be a power loss if head gasket was blown or cracked?
Never do it with the engine hot. It will boil over rather quickly. Check it with a cold engine. If a head gasket is compromised, the cylinder will be pumping exhaust gas (bubbles) into the cooling system, so it will be almost instant (alowing time for the bubbles to reach the tank). Once the coolant warms up (few minutes) the level will start to rise. Now would be a good time to get the cap back on and locked down as it is about to overflow.

You would not notice much of a lack of power unless it was really bad, but by that time other signs would leave no doubt.

03-05-06, 10:28 PM
Exactly. ^^^

#1, you are not overheating. It's cold in Wisconsin and Illinois too. Bad head gaskets generally overheat. So, that's on your side. No overheating.

#2, Ranger is right, you'd see the bubbles right away. It sounds to me like it boiled over. With the cap off, it'll boil over at a LOWER temperature.... Again, that's good for you.

#3, bad headgaskets don't make it smell like coolant in the car. Rob S says heater core, which is a possibility. Any kind of small leak in the engine compartment could cause that smell, and be a very easy fix. Small leak in a hose, seepage around a thermostat, anything....

I also agree that it's a little fishy with the dealer.... Get a second & third opinion from 2 more places if you're not sure. Tell them what you told us. Not overheating, smells like coolant.

These dealers... any time I'm at a Cadillac dealer, I swear, a salesman comes up to me and wants to buy my car. The last guy wrote his home number on the back of his card. I always take the opportunity to point out that THEY DON'T MAKE ELDORADOS ANYMORE, so what am I gonna replace this with???? We need to hammer home the message: bring back the Eldorado!

Sorry. Get another opinion, but I seriously think it is not a headgasket at the moment, from what you are saying...

03-07-06, 05:54 PM
Good advice.

There's a bad habit of folks blaming the headgasket too soon.

"Engine idles rough? Head Gasket!"

"Coolant low? Head Gasket!"

"Brokeback Mountain? Head Gasket!"