What kind of A/C compressor drive does the Gen II have? When I turn on my A/C, I always get a low pitch, whirring sound that eventually subsides when the pressure is stabilized. The A/C always blows cold air and always works correctly. The noise lasts longer when the car has sat for a longer time. If the car sits off for5 minutes that start up noise in the A/C last only about 15 seconds. If the car sits overnight, the A/C noise last about a minute or two, then everything quiets down. The A/C ALWAYS blows normal, cold air. Any ideas?