I've got a 2003 SXT with 67000 miles.Over the past week it has started to over heat only when the A/C is on. It will redline. When driving without the A/C on, the temp stays in the middle, regardless of traffic or driving location. Also, when A/C is turned off, after getting close to overheating, temp goes back down quickly. I just replaced the thermostat last year. Any ideas? And thanks!!

 

You probably just need a new fan clutch.

 

Agreed. The condenser is getting hot because the a/c is on and you are not pulling in enough air to cool both it and the radiator. I am thinking a clutch fan. Also things to look at is to make sure the fins in the condenser are clean of debris. Take it to the car wash open the hood and spray out the condenser really good and see if that cures your problem. If not I would replace the fan clutch. I am wondering if the radiator needs to be reversed flushed but I'm thinking that is a last resort because of consistent temp when the a/c is off.

 

Ok, will try the cleaning first, then look at the clutch fan. Thank you both!

 

Not a problem.