jbwilli

Car is overheating. The coolant fan runs when a/c is selected, but when a/c is not selected, does not come on until water temp is mid range or higher on temp gauge, and it goes back off befoer engine cools to normal oeprating temps. I see many posts with similiar problem.

The in line coolant thermostat is good...removed it and placed in water on stove, and it opens wide just before boiling, appx 190degress, and closes when removed. Repeats and does not stick.
Replaced the ECT sensor, no help..old one was good.
Entire coolant system was flushed several months back.
Coolant level is correct and with recommended fluid.

I do not suspect the coolant fan relay, as the fan operates fine when a/c is selected, and also noted it runs during 'start' briefly. If either the relay or fan motor was bad, the fan motor would not work at all.

The coolant fan motor comes on eventually, but at high collant temps.

I see reference to a coolant fan thermostat that tells the fan when too kick on, at a preset temp.
I would expect it to come on around 195-200 degrees?

CAN ANYONE OUT THERE CONFIRM THERE IS A COOLANT FAN THERMOSTAT/SWITCH THAT KICKS THE FAN ON RELATED TO TEMP, AND IF SO, WHERE IN THE HECK IS IT LOCATED?

THANKS ALL...PLEASE HELP!

pontiacmrc1

Usually the coolant temp sensor controls when the fan's come on at what temperature. If the fans are comming on when the A/C is on, and they come on when the car get's to a certain temperature, then I would have to say the coolant temp sensor is good. Depending on the car, the fans might not come on until the car reaches 212-215 degrees, maybe even 220 degrees. My ole lady's 1996 Cavalier, the temperature guage used to get to almost red before the fans would kick on, but then the head gasket started leaking, so when I was in there, I put a new thermostat in it, now it usually only goes about 3/4 the way up before the fans come on. As long as the fans work when they're supposed to, and even tho your thermostat open's and closes in a pot of water,I would sugguest putting a new one in it, and see if that helps. That's all I know to do!