I'm having a problem with my truck overheating when I run the AC lately. I have a 2002 crew cab S-10, 4.3 V6. Ichecked the charge of my AC, it's right about where it needs to be. I'm not sure what else to look for, as it only overheats when I run the AC. Anybody have any suggestions? These days of driving to and from work everyday not running the AC isstarting to get old, especially when we're in the high 90's with high humidity. Thanks!

 

First thing is to check the engine cooling fan is turning.

The A/C condenser is located right in front of the vehicles radiator. Since the condenser is emitting heat check to make sure it's clear of any debris as well as the rad. You want to make sure there is an unobstructed air flow through the cooling fins for both. This is a simple and cheap fix that can be done with a garden hose.

Other things like a circulation problem with the water pump or rad , the rad cap not venting properly could also contribute to the problem.

 

Also check the thermostat to make sure it is even engaging the aux fan at temp - is the temp fluctuating at all without AC?

 

The temperature is not fluctuating at all when the AC is not running. Just when I turn on the AC the engine starts to overheat.

 

I can run the AC all day long in the driveway, but as soon as I hit the road it starts overheating. Any suggestions?.........all the other ones have checked out okay.