My sons 03 GC is overheating. I recently replaced the radiator but now the check gauges light comes on and the temp is maxed out. I'm hoping it's a basic thermostat. Should I have him drive without the AC on to see if it's compressor related?

 

The A/C won't really cause an engine to overheat, but it can cause the engine to run hotter if the cooling system is not up to snuff. The A/C and cooling systems are two different systems. Replace the thermostat with a 195 degree t-stat, replace the hoses, make sure the fans are working, replace the radiator cap, run a 50/50 mix of coolant, and make sure you have all of the air out of the cooling system. You should be good after all of that.

 

If the electric fan isn't coming on it is probably the relay. See this write-up. http://www.jeepslimited.com/index.ph...=37&Itemid=127
Also, there have been many reports of the vanes on the water pump breaking, causing overheating. Allow it to cool, then remove the radiator cap to verify the coolant is circulating through the radiator.

 

I had the complete radiator replaced three weeks ago so it's probably the relay? And if that's the case, I wonder if taking to my guy is worth the labor cost to replace?

 

If I had the rad replaced 3 weeks ago and it was overheating already I'd be telling them to come tow it in and correct the problem before it causes engine damage.

 

I guess I'm afraid they will tell me its not what they replaced but another issue causing the problem. I was in a jam when I had the radiator replaced and not too sure I want to give this guy more money.

 

When you took it to him the first time did you tell him to replace the radiator, or did you ask him to diagnose why it was over heating? If they were to diagnose the over heating and repair it, it's kind of on them. If you just told them to replace the radiator for you, it's kind of on you.

 

+1 on the relay. also check the connection where the fan plugs in.

 

I really didn't tell them anything, it was pretty obvious that the radiator itself failed (part of the radiator itself blew out). I guess I assumed they would diagnose...

 

How did the Jeep run in the three weeks between the radiator replacement and now?

 

It could be as simple as air in the system, pretty common actually and something the shop should have caught before letting the vehicle go. Air in the system can cause the t-stat to not open correctly, and can also cause sensors to read incorrectly. Could also be a defective radiator, back when I turned wrenches we got a radiator in that some mice had turned into a nest, completely filled one side with vegetation and trash... was pretty cool, actually, but not to the customer that had to wait an extra couple hours for the replacement replacement radiator to show up.

If the shop has any sort of self-respect, they will readily take the truck back in and work to correct the situation.