last year i was sitting in my car with the ac running, everything weorking fine. waiting on my mother. all of the sudden the thermostat shot up hot and my air blew hot air. I shut the car off and all was well. However, we had no air. I tried a few cans of freon, worked slightly for a day of so but that was it. Then i had the entire system drained and refilled and checked for leaks. was told there were none. again it worked slighjtly for a few days and that was it. Now i have tried to cans of freon with the dye hioping to see something but not yet. The freon helps it blowslightly cooler air but nothing like it used to. aklso when i sit in idle mode the car seem to get hot when ac is on. please advise..