i actually had the same question, i read the thread i actually have this problem with my car, its a 1996 mits eclipse, just got a brand new radiator, water pump, but it tends to build up pressure in my overfill and then dumps it out, then i get less coolant in my radiator causing my car to overheat, it is an electric fan and i was thinking that it might not be kicking in as often so that may be the problem, could it be just a new radiator cap? if you guys can help me out that'd be terrific. i'll try the heater core flush. that may be the prollem!??
