My 1987 560sl air conditioner will randomly blow HOT air. The air conditioner will start out working properly...When I shut the car off & then return to restart it, the air conditioner will blow HOT air instead of Cold air.. The compressor has recently been replaced & refilled with the proper coolant. Somethimes it will blow the cold air & then it will suddenly start blowing hot air. Does anyone have any ideas what could be causing this problem? THANKS