[ogre1967]

Usually when you run your engine with yourt ac on you are putting more load on your motor so it works harder and will want to run a little hotter. when you shut off your motor it will typically overflow into your overflow tank and then as your motor cools it will draw the over flowed coolant back into the radiator. This is normal as long as your temperature on your gauge stays within the normal operating range which is around half way on the gauge.