1983 240d, I have been getting somewhat lower gas milage recently. Last night when the car was idling I could hear a sound comming from the engine.. It is a hard sound to explain, but it sounded like a slow pulsing growl. It's been cool here and I have not needed my A/C for a few days. Today, I didn't have the A/C on but when I opened the hood I could see frost on the large hoses of the a/c system. I looked down at the clutch on the compressor, and noticed it was engaged. I checked the control knobs and they were in the off position. I removed the fuse controling the A/C, the clutch still remained engaged. My question is, is there anything else that can cause the a/c clutch to remain on. If not, can the A/C clutch be replaced without removing the compressor. Any help would be appreciated.