'97 Cam cooling way too quickly...

[EddieHaskell]

On Saturday I noticed that my coolant is cooling down way too quickly. I was driving home on the freeway, and the air felt slightly chilled, but when I got off the freeway and was sitting at a red light, my coolant temp dropped from 185 to below 160, and the vents were blowing really cold air. When I began moving, the temp climbed up to 185 again, but would become cold whenever I idled for more than a few seconds. It is winter here, and the temp was only 17 fahrenheit last night, but I've driven this car in temperatures below zero fahrenheit and it never had any problems.

I'm wondering if I've got a bad thermostat, but in past cars, it's always led to an overheat condition, not a chill like I'm experiencing now. Any ideas? Thanks a lot!

[EddieHaskell]

Sorry, I'm recovering from a hangover, I meant to ask, do you think it likely that the thermostat is stuck open (hence the freeze-o-matic) as opposed to stuck closed (ala my overheating Supra)? Any time one has gone bad on me in the past, it's always been stuck closed. Thanks again!

[BobbyZ72]

Sounds like bad tstat to me, like its not closing all the way. Id change it out and flush the coolant.

[EddieHaskell]

Well, I swapped out the thermostat and gasket. I did it correctly, and followed the directions. She hit 180 degrees and I could feel the coolant hose warm up as coolant passed through.

I took it for a test drive and ARGH! The coolant temp gauge would rise up to 210, all the while the vent is blowing freezing air, and then suddenly the gauge would drop to between 170-180 and it would suddenly blast hot air. The cycle would repeat until I decided to shut down.

Now I'm wondering if I've got a leak, or the Dexcool garbage has turned to sludge...

Sadly, I am defeated and am taking it to the shop so I can get bent over a chair by Pete Bauer Pontiac...

[EddieHaskell]

Sorry for scrolling, this will be my last post on the subject. I took some digital photos, and even though that is the original thermostat and dirty (99K miles) it didn't appear too corroded. I'm glad I changed it nontheless but here's what it looked like.

Original thermostat pic #1
Original thermostat pic #2

Thanks for all the help folks, and thanks for putting up with my frustration. My thanks to you all.

[Dawizman]

Sounds like you might want to flush the system. Might be some sort of clog in there.

[BobbyZ72]

i would first try taking the two heater hoses off and flushing the core out with a water hose, see if that helps.

[Rob Bell]

And make sure you bleed the air from the system, especially if you have the bleed valve

[EddieHaskell]

I just got the car back from the shop, the water pump had sprung a slow leak and air was getting into the system. Replacement cost was $414 at Pontiac.

I'm still glad I swapped out that thermostat to a 180 degree tstat; she's running like a top.

Thanks to all for the advice, it was reassuring, and gave me some great pointers for future reference.

[ February 21, 2006, 02:52 PM: Message edited by: EddieHaskell ]