Trying to diagnose my girlfriends 1997 Cavalier, has the old 2.2 ohv in it. Just changed out the headgasket and thermostat. The car runs at normal operating temperatures when driving 55 and under/city driving, but when you get on the highway it runs just in the bracket and blows a luke warm air out the vents. It is also sucking through gas, is this because the motor is running rich trying to heat up?
I was thinking of changing the surge tank cap, or could it possibly be a thermostat yet again?
Or one more thing, more air in the system? Should I try bleeding it out? What method do you guys do, the bleeder valve or pull a heater core hose?
Cheap one from autovalue... did some research and thats probably the culprit right?
Should I buy the Stant or NAPA premium one?
Next step I'm going to change the surge tank cap if the thermostat doesn't fix it.
Get either one of those. Also look into a radiator cap. Simple and if they go bad they sometimes cause the car to not heat up since the system cannot build up pressure. Also try bleeding the system again, just run it, and keep the surge tank cap off till no more bubbles, usually takes like 20 mins since we have a wonderful closed system, blah. Lol. But usually air pockets will cause the car to over heat. I dont think the surge tank would be a issue since they will just leak not stop the car from heating up. Other then that, try a piece of cardboard infront of the radiator to block some of the air coming through, and also check to make sure the cooling fans arent staying on. Goodluck!
Thanks a ton for the help, gonna grab a surge tank cap just for the hell of it and kill 2 birds with one stone hopefully...
I'll post again after Friday if this doesn't fix it.
