Chevrolet Repair: A/C problems, r 134, infront

Question
I have a 91 caprice and it overheats only when my A/C is on. My fan and clutch
works fine. Also it was upgraded to R-134 recently. It usually happens when its
hot

Answer
If the fan and clutch are good, make sure the condensor infront of the radiator is clean.  Try blasting water from a hose to spray off debris.  Also make sure the coolant is good.  It may have a good enough percentage to run the car cool, but when you engage the A/C you create a load on the engine.

Jimmy