96Cutlass Supreme Overheating

Hello, all! I am new to this forum as a member, but enjoy reading & have learned a lot from posted threads. Today I have a problem with my 96 3.1L, 165K overheating. I have ruled out the obvious- no leaking Dexcool, radiator is full. I just replaced the thermostat. Anyone with this 3.1L knows about the faulty intake manifold gaskets. This job has been done twice on the car. I do not have antifreeze in the oil. Here is what happens... sometimes temperature gauge rises way past half, then goes back down, and all is well after vehicle is parked. Engine is not hot. On another occasion the gauge remaind about 1/3 of the way up, and smoke was coming from the hood. After the smoke cleared, I opened the hood- of course enging was super hot - but still no leaks! I believe the fans come on. Is it possible that the new thermostat is just as faulty as the one which was removed, or maybe we simply added too much water to the coolant mixture? No one can seem to figure this out. Any info will be much appreciated.

Welcome to AF.

You either have an air pocket trapped in the cooling system or faulty head/intake gaskets.

If the intake gaskets were done before 2003 then you have the old style gaskets which are prone to blowing out.

hope that helps.

Thanks for responding. The last gasket job was done in 05, so they should be the new style. Assuming then that it may be an air pocket, how can that be removed? Do you just flush the cooling system?

Thanks.

No flush to purgue the air.
Should be a bleeder valve on the pass side above the water pump on the black tubing.

Start the engine allow it to warm up and with the heater on full blast.
Loosen the bleeder slowly to allow the air to escape(if thier is any) when coolant flows out shut bleeder. Might do this two or three times, it does help if the front end is elevated a little.

Here is a pic, bleeder is at the top under the word "at".
http://i28.photobucket.com/albums/c242/xeroinfinity/waterpumppulley.jpg