97 T&C 3.8L OVERHEATING
 

I have a 97 t&c 3.8L thats overheating when the a/c is on only, i have checked the t-stat its ok, water pump is new and not leaking, radiator flow is fine,found no leaks at hoses or anywhere else on engine. I do not have white smoke from exhaust or a sweet smell coming from it either. The temp gauge seems to go up about 3/4 of the way when im driving between 60-65 mph with a/c on.My fansare coming on at the right time.I have to refill the overflow tank every couple days. I checked antifreeze tonight and the boiling point says 126 degrees im thinking i may not have enough coolant in system. What should the boiling point be on these engines? Anyone know what else i should be checking for or do to correct this?