My Wife's car overheated after the check engine light came on. After a quick look, I found that the belt is tight, the fans are working properly and the coolant was low (probably due to the overheating itself). I topped up the coolant and ran the car again, couldn't see any leaks, but after running the ac for about 5 minutes, a chirping, grinding, sort of noise began from the compressor/clutch. The noise stops when the ac is turned off, so I'm thinking the problem is with the clutch only. Can the clutch be replaced with the compressor in place, or does the entire unit need to be replaced? Dealer says they can't look at the car for a week, and I can't afford to be without it that long, so would like to fix it myself if possible. Any help or advice appreciated. TIA.