overheating

i got a 88 maxima and it has an overheating problem. when im going down the highway with the ac on the temp gauge will go up to 3/4 the way up and keeps rising. i changed the thremostat and flushed the radiator. the fans do work. if i turn off the ac and put on the heater the temp will fall back down.

I'll suggest getting a performance UDP and adding some redline to ur coolant. Ur in Cali so u dont need as 50/50 coolant. maybe more 75 water. But what do I know.

ok cool thanks for the help. ill try that

my civic is doing the same thing but its burning coolant every couple of weeks check the head gasket it might be going bad.