Just replaced the thermostat (180deg) and flushed the radiator. It is very hot here in Florida (95 deg), but the car runs at a decent temp. When I turn the air on, it moves another whole tick (on the tempgauge). When I turn the air off, it slowly drops temp again. Is this normal? There are no leaks. Should I ad water wetter? Stock fan and radiator (I think). Thanks!