I recharged my AC system at work 6 weeks ago and it works perfect. The last two weeks or so its been acting weird. Everytime I turn the AC on, when the compressor kicks on it makes an awful squealing noise. Saw my belt had a little fraying on one side so I replaced it with a Gatorback belt. Didnt solve my issue. There is an occassional belt squeal at cold start up as well.
I tried the AC again the other day and after a few seconds of it being on my check gauges light came on and my volt meter went from 13.5 to 9.
Any ideas?
1999 Cherokee, 4.0, AW4, 194k

 

Likely the belt simply isn't tight enough. Those things must be pretty snug or they will slip and squeal. Not sure about your drop in voltage. Is the A/C still working?

 

Re-tightened the belt and it still squeals.

Could there be a bad pulley? Water pump is brand new, only has 2k miles on it. Alternator was replaced 6 months/4k ago. AC compressor was replaced 35k ago.

 

To what spec?

 

To tighter than is was. I feel like its too tight now.

 

Probably still not tight enough. Go to NAPA and get a KR2 V-ribbed tension gauge. I had mine cranked super tight enough that it wouldn't squeal. Checked it with the gauge and it still wasn't tight enough. On my little car, it has an spring-loaded tensioner that you put a wrench on to release. Almost need a cheater bar on that wrench to back it off. These things have to be incredibly tight.

 

Whats the spec on the belt tension?

 

What's up? I had the exact same symptoms recently. Kept hearing a continuous squeak then later squeals and it seems they were coming from the water pump or ac compressor area so planned on chening those. Then one day was driving down the road and smelled rubber burning and a louder squeaky grinding. When I popped the hood I sat the idler pulley wobbling badly. Once I got it off this is what I found:



Headed right to Crazy Rays and grabbed a "new" one

 

180-200 lbs. for a new belt and 140-160 lbs. for a used belt. A belt is considered used after 15 minutes of run time.

Wouldn't be a bad idea to back the belt off and give each pulley a wiggle and a spin to make sure they don't have excessive play and turn smoothly and freely. It's a good thing to check whenever you put a new belt on.

On the little car I mentioned earlier, I had a belt that was old and stretched out, and starting to flake apart on the back. The tensioner pully also had a bit of a whine to it. Put a new belt on and the whine got worse. The extra tension of the new belt was more than the pulley bearings could take and if failed a week later.