I have a 2003 Chrysler 300M special. It is overheated. I just changed the thermostat. But it is still overheating. When the car warms up, I check the radiator bottom hole, it's cold. And I see that the temperature gate go all the way up. Then when I turn the heat on maximum, the gate goes down halfway. But it is still overheat. My car is 165k miles. I don't know what is going on. Can you help me fix with that problem? Thank you.

 

Thermostat is installed correctly with the spring end towards the engine correct?
Did you open the bleeder when you refilled with coolant? Bleeder looks just like a brake bleeder, located in the front of the intake just behind the upper hose.

 

I did everything you told me. But it is still overheating. Could you help me again?

 

Do the fans work properly??
Many poss causes but let me assure you "head gaskets" is last on the list for these engines.
Best advice I can give is search and read :http://300mclub.org/forums/index.php

 

I'm not sure the fan is working properly or not. But when the engine warms up, both fans turns on. And its running about 1 minute, then the fan on the passenger side turns off, but the other one is still running. When the engine is overheated, the fan ( the driver's side ) runs high. The fan on the passenger side is still not on. Could you please help me?

 

When I pulled out the high fan replay, the fan on the passenger turned on. I just had a guy come take a look, he told me: " the water pump is bad, it doesn't circulate in the cooling system. That's why it was overheating. " Could you help me fix that problem?

 

At 165k and an 03 year car has the timing belt been changed yet? Not that it is causing overheat but 105k/84 months is the recommended interval. Typically referred to as Timing belt/ water pump job as the belt needs to come off to do the pump.
Both fans should run either high or low at the same time.
Loads of good information and help with this common issue at the site referenced previously.

 

Thank you very much you guide me.
You have a happy New Year.