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Overheating with the AC on

Talyn

NAXJA Forum User
Need a bit of help with over heating with the AC on. This is on my 97 w/ the 5.2L engine. It will run all day at 210*, even pulling a 2000 pound trailer. However, when I turn the AC on it starts to overheat. The water pump was replaced 4 or so years ago when I got it and I checked it at the beginning of summer. The radiator was replaced about 2 years ago when a stick went through it and the t-stat at the same time. The Fan clutch has been replaced and it definitely locks up. The belt tensioner has also been replaced with an OEM unit and the fan belt at the same time. No air in the cooling system and the coolant is clean. Radiator and AC condenser are clear of debris. Fan shroud is in place as well. No signs of a head gasket leak either. It mostly happens in stop and go traffic, which indicates and air flow problem. But both the fan and fan clutch are fine. I'm out of ideas.
 
We recently swapped in a new radiator and in the process we cleaned the condenser with a soft nylon bristle brush. It had a lot of junk on it - dirt, feathers, bugs, etc.

Larry (Father-In-Law) watched a video done by Eric the Car Guy where he uses a cleaner to wash the condenser. We first used the brush and then soaked it in the cleaner two times. There was all kinds of black and brown stuff that seeped out of the condenser. We washed it with water and installed the new radiator. It now can sit and idle with the AC on and never get over 210*.
 
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