My '95 BMW is running like a champ. Today when I drove to Marion, Findlay and back, I was using A/C, and the car was very comfortable. However, once I got off the highway, I heard what sounded like hissing under the hood, and it was RPM-specific. I could feel the compressor engaging and disconnecting, but when I turned down the stereo, I realized it was an occasional squealing/slipping noise.
Admittedly, I haven't had a chance yet to look at whats going on underhood, but would this jibe with just the A/C clutch going out? (A/C still engages and blows cold, but compressor occasionally makes noise).
Of course, I'm hoping it's just the A/C clutch, and not the compressor.
How do I diagnose the system?