ok first off, it's not my car, it's my GF's sister's car. she has an '01 Galant and the car starts to overheat about 5 mins after it's on. it hovers about 1/16" under the red dash... unless i turn the A/C on full blast. i checked the usual things like radiator fluid, thermostat (replaced) but i'm running short on ideas. don't wanna take it to a shop unless we have to, and i honestly have no clue about mitsu's so i figured i'd ask ya'll.

any help/suggestions would be appreciated.

 

I was going to say thermostat....thats all that would make sense to me.

The reason for the A/C is because when you turn that on it also turns on the 2 fans under the hood behind the radiator. Individually they are controlled by the thermostat... that would have been my first guess. Since you replaced that... i really dont know what to tell you. Maybe look for a loose wire harness.... anything. Hard to say without being there.

So do the fans come on at all without the A/C?

 

well one of the fans comes on for a few seconds, then it dies out. when u hit the AC, they both turn on...
the 2nd fan (smaller) tends to turn on and off randomly, and when u stop at a light (idle) it actually goes down a few temps, then rushes up as soon as you go above 1500 RPM.

 

Hmm, interesting.

Coolant levels normal? Notice any smoke coming from the exhaust?

 

coolant levels fine. flushed and re-filled with antifreeze/water. no smoke at all...

i was thinkin maybe a sensor or something... i was hoping this was a 'common' problem and someone would say 'just do this' and it would solve it [:@]

 

You see, if you hadnt replaced the thermostat then i would have said that.

Maybe the one your replaced it with is also f-ed

 

Ive heard of heater cores causing **** like this...

 

is the engine actually hot? i mean, it might just be an electrical mess and the engine isnt actually heating up...

 

Coolant temp switch. There are two of them, one for the a/c (seems to be working just fine) and one for the fan. It sounds like your coolant temp switch is bad. I'm not talking about the coolant sensor that sends coolant temp info to the gauge. The temp switch usually has two wires leading to it, while the sensor has only one.
Another reason for overheating are air bubbles being trapt along the passages. To get them out after a flush, you have to run the car, watching the flow of coolant moving from the radiator cap opening. It will eventually rise and burp up air. If you didn't do this or have this done, air bubbles are causing poor flow.

 

I have the same problem with overheating. But I also have smoke from the exhaust when I take off if I stop at a light or let it idle for a while. What could cause this?