Over heating - Bad thermostat? Air in system?

[Skrappi69]

I changed out the heater core and thermostat on my 99 Prix. I flushed the entire system. Started overheating like mad. Heater temp would fluctuate. Possibly an air bleed issue?

When running the motor with the heater on the air bleed screw would just sit there and hiss for over 30 minutes! No water. Only steam. I checked for coolant leaks and I am good. The oil is clean of water. Car runs fine it just gets incredibly hot!

How long should it take before I see water from the bleed screw? Possibly a bad thermostat?

Thanks!

[Bio248]

moved to general tech. this is not a how-to thread.

you should start with the radiator. make sure that is full and stays full, then cap it. then start at the bleeder screw.

[Skrappi69]

Sorry about posting in the wrong area. Do I move it or do you move it to the other category?

[Skrappi69]

Checked the radiator. Full. Any other ideas?

[Fivefingerdeathpunch]

dont run the heat, at least I dont when I bleed mine.

195 thermo right?

I just let it idle up to temp and once the thermo opens it starts to come out the bleed screw, I only turn it about 1-2 turns, just enough for it come out.

[Skrappi69]

I tried both with and without the heater running. I made sure the coolant level was maintained.

Could it be the thermostat? The new one I installed is rated at 195.

Long and short, tried everything and am left thinking it's the thermostat. Unless
Of course anyone else has a better idea.

Thanks

[BillBoost37]

Having owned a Honda in the past, I understand why there's a suggestion to run heat or not run it. That's because some cars (not ours) have a valve to block off th heater core and bypass it. Oour cars continually run water through the heater core, therefore running or not running heat has no effect on bleeding.

If you have a 3800 and you think it's not bleeding properly, by filling at the radiator and using the bleed screw. Remove the thermostat housing and thermostat. Fill via funnel right into the LIM. Let it sit for 5-10 minutes if the level doesn't automatically go down on it's own.

When a 3800 is very stubborn, pull the stat and housing, fill at LIM. Been there..fought that battle.

[Skrappi69]

Thank BillBoost37. I'll give that a shot and let everyone know how things turned out.