I recently replaced the relay's for both the cooling fan and the A/C condensor fan and had the Air Conditioning recharged. Both fans seem to be working fine but the car will start to run hot and the temp. gauge will begin to climb only when the climate control is turned to cool. It doesn't matter whether the A/C is on or the fan is blowing. It will only do this after driving for a while. If I turn it to warm for a little bit it will cool back down. Then if I turn it back to cool I can drive and it wont do it again for a while. The A/C will still be blowing cold as well, even when it starts to overheat. But like I said it can be turned to the cool side with the A/C off and it will still do this. Sorry if this doesn't make sense. But if anyone can lead me in the right direction I would appreciate it.

 

Still??? Damn... The thermostat may be stuck closed, or the radiator might be clogged. Either way, it's something in the cooling system, not the AC, as you probably figured. When you turn it to heat, you're using the heater core to help cool the motor. Thermostat is easy and cheap, if you haven't replaced it, I might start there. Also make sure you have enough coolant...

 

Coolant is good, And I just put an OEM thermostat in not too long ago. I never had A/C before so I just left it turned to hot and forgot about it. But man when its +100 degrees outside even if the heater isnt on a little bit of hot air still comes out and that sucks. I think you might be right about the radiator though. that thing is so old and the bottom tank looks all corroded. I can barely take the drain plug off and on, I have to use pliars. I guess even if its not the problem it would be good preventative mantainance. IS there a good way to test a radiators flow?

 

maybe your rad cap isnt holding pressure. get a rad pressure tester to test the cap and the rad itself.

 

Thanks Ill try that.