View Full Version : Coolant Issue "00 STS"

04-06-09, 05:26 PM
I just bought a 2k STS, beautiful BTW, silver w/ black.....
Has 111k on it and got it for $4000.00

Did a check on the coolant at the guys house, no bubbles when cold in the surge tank and doesn't appear to have any debris in it either.

Went ahead and brought it home, and filled the surge tank up to "Full Cold"
which it took about 1/2 a quart.......

Next day after about 18-25 miles after the refill it was back down to where it was the day prior...Bear in mind it was "EXACTLY" where it was when I brought it home.

I feared the worse and immediately took it to my mechanic, which held 20lbs on the system for over 15mins, granted the engine is warm at this point but they know all about the Cadillac "Head Gasket" issue, and they are 99% sure it is not a problem at this point, but most likely the system is low and just was filling itself back up and may require a little more over the next day or two, but not to worry till the end of the week if it is still requiring top off. How does this sound to you guys????

04-06-09, 05:42 PM
....Went ahead and brought it home, and filled the surge tank up to "Full Cold" which it took about 1/2 a quart.......
Was the engine cold when you did this?

FULL COLD means exactly that. The reservoir should have approximately 2" of air space when cold to permit the coolant to expand at operating termperature without pushing fluid out.

04-06-09, 06:43 PM
my 2001 dts has coolant level of below the full cold level. i have added some but it just dropped back down to the same level as you say..
i have had my car for over 50K miles and it hasn't changed what so ever.
i am no concerned... plus i just got back from a 900 Mile trip with only stopping to fuel up. and it was perfect!
i would not be concerned

04-06-09, 06:49 PM

Yes, it was cold when I filled it, both times.


mine is doing same thing, once it gets down to about the last inch or two of the surge tank, that's where it stays

04-06-09, 08:31 PM
Be advised that pressure testing the system is not likely to show a bad head gasket unless it is so bad that it would not even be a question. Now I'm not saying that you have a head gasket problem, just want you to understand. I would have said you have a leak somewhere, but a leak WOULD have been detected with that test. Just bring it to the proper level (about 1/2) and keep an eye on it.

04-07-09, 10:33 AM
Thanks Ranger,

Im not convinced I have one either, but like you said, I will be keeping a close watch on it.

Thanks ya'll for the help, I appreciate it.


04-07-09, 09:58 PM
Well, if anyone is watching this......

The surge tank has stayed ful for over 24hrs now.
Guess it was just low.....Will still keep an eye on it though.

04-07-09, 11:10 PM
It is a sealed system so it should never get low. Keep a close watch on it.