Dodge: RUNNING HOT, rad cap, dodge truck

Question
1998 1500 SERIES DODGE TRUCK RUNS HOT ONLY WHEN USING A/C. NEVER ANY OTHER TIME. NEW RAD. CAP, T'STAT, WATER PUMP. IS PROBLEM WITH A/C OR COOLING SYSTEM?

Answer
a pocket of air trapped in the radiator will cause an engine to overheat.If you've replaced the thermostat and pump,it has to be the cooling system.Make sure the radiator has no builup inside on the coils.if it does either replace it or have it rodded out.Or try flushing the system.Also check the blades on the fan to make sure they are not bent or cracked.