Truck Running Hot w/ AC ONLY!
 

Alright guys,

I recently purchased a 1997 Silverado 1500, with a 6.5 TD. This is my first diesel pickup.

The previous owner did a homemade EGR bypass. I'm not sure if this is affecting the cooling system or not. I don't even know if everything is correct.

The problem I'm having is my truck runs hot when the AC is running. It doesn't matter how fast or slow, it just creeps up to about 235 and stays there unless I cut the AC off. I replaced the thermostats, added coolant, changed the oil, and all filters. The fan comes on when the truck is parked, not sure when I'm driving....however the clutch seems tight.

I'm at a loss for what to do next? Any suggestions? :scare2:

Have you checked the water pump, belts, made sure the radiator is clean