I have a 05 TL and after i run the AC for a while and park the car the next time i start up it makes this pretty loud purging sound. I took a look the last time this happened and it smelled like it might be AC freon hitting something hot and burning up but what would cause this? It looks like it's hitting a piece of metal below the radiator but it doesnt smell like radiator fluid? I've just been driving with the A/C off for now and it hasn't occured since...(knock on wood) but it's hot as hell out here any suggestions would be greatly appreciated!!!