AC clutch or compressor???

This is copied from my thread on YotaTech.

'97 4runner, auto, 4wd, SR5, 3.4L. I headed out Friday on 1.5 hour ride when I left, the A/C was COLD as a always. When I got close to my destination, I noticed it was NOT quite as cool. On the way home it became obvious that the A/C was no longer cooling. It may have been a bad idea, but I stopped by O'Reilly and got a DIY can of 134. It didn't make any difference and the system didn't wasn't to take it in. After getting home and running the truck with A/C running wide open I watched the compressor. What I found was that the A/C clutch would occasionally engage, but with all sorts of wailing and gnashing of teeth. It was NOT rotating freely and the belt would actually start to smoke. When this happened it would only last a few seconds and then the clutch would disengage and things were normal until the clutch engaged again. When engaged, the pulley WOULD rotate, but not smoothly. My question is this. Does it ever happen that only the clutch will fail w/o the compressor failing or is it more likely that the compressor is dying and the belt just doesn't have the torque to turn a compressor that's on it's way out? I'm anything but an A/C expert, but I do have access to vacuum pumps and any tools to do the mechanical work. At 306,000 miles it's hard to justify spending big money on a repair. I've had very good luck with buying used OE parts from eBay. Most of the sellers show the vehicle with VIN and odometer #'s. Most parts have come with lengthy warranties. I know there are REAL experts here. Assuming I have competent help, is there a reason NOT to work on this myself. As it's NOT working now, I'm not sure I have much to lose. I have the ability to recover refrigerant as well. Thanks in advance!

 

@CodeSeven helped me with my AC issues, maybe he can help here

 

yep. the clutches can go bad without the compressor going bad. but your belt smoking is telling me it's the compressor thats gone bad. youll need to have it fully replaced. compressor, orifice tube, drier, and a really REALLY good flush. it sounds like there's shrapnel in the system and that's what's grinding.

 

That's NOT what you were supposed to say! I know you're probably right, but since the new compressor comes with the clutch, I'm going to take the belt off and jump the clutch switch so I can get my hands on the old compressor and see what it feels like before I fully commit to doing the whole job. I appreciate the help!

Charles

 

that's actually a very damn good way to go about diagnosing it. good luck!

 

OK. The plot thickens. On the way home from work I decided to turrn the compressor on and see what would happen. It didn't sound all that wonderful, but I got cold air for 3 or 4 minutes. I don't know for sure, but I wouldn't think I'd get ANYTHING if the compressor was locked up. I'm hoping this MIGHT mean it's the clutch instead. What's the thinking here? Thanks!
Charles

 

most of the shrapnel has already passed. but this is starting to get out of my limit of expertise. I can only tell you what CAN happen in the AC system. still put straight power to the compressor and spin it manually (it wont spin easily, which is normal) to see if you can feel any "grit" inside as the vanes rotate.

 

Thats my plan for this weekend. I think you're right that I'm not going to REALLY know anything before I get my hands on it. I really appreciate the help. I'll keep this thread updated as I progress. Thanks.
Charles