Well, I installed my new (used) compressor the other day and installed all new belts today and drove the 60 for about 20 minutes. When I parked back in the garage, it sounded like something was boiling at the compressor; kind of a "hissing" sound that lasted about 30 seconds. I am only running the compressor clutch, since I have not charged it with R12 yet. I do not have the compressor wiring connected and the A/C button is off. What could that sound be?