tacmedic909

I have a 99 XJ 4.0. When I turn my a/c or heater on the belts squeal very loudly. I have tried tightening the belt but I'm not sure how tight this needs to be. I am hoping this is the issue but what else could it be? I've noticed that it only squeals when the compressor kicks on and the voltage meter shows a slight drop. When I press the gas pedal and increase RPMs then the squealing stops. Could this be a bad alternator or bearings bad in the compressor and if so how do you check?

Ant.

I am thinking your belt is loose..

Ant...

Bustedback

How old is the belt?

tacmedic909

I am not sure. It doesn't look that old.

Bustedback

When in doubt change it out.

ABBA-ZABA

Try to check if the clutch mechanism on the a/c compressor is working properly. I dealt with this same issue and found that the clutch tends to freeze, so instead of paying for a new compressor or rebuild kit I just got an a/c delete pulley. If you don't use a/c it's a quick and inexpensive fix.

DFlintstone

I have this "canned"

Soaping Belt


Tight, tighter, tightest the darn new belt would still chirp.

Finally in desperation I went out there with a bottle of Dawn dish soap and the garden hose. Idling, I got it wet, then squirt soap on both sides, rinsed some, and soaped a little more. Let it idle a minute all soapy. To end, I ran the hose slow on it running for a couple minutes. Bingo! That solved it. There was some sort of coating on the new belt? Idk.

I normally run my belt as loose as I can, and still have the alternator not slip with the blower on high, and lights on brights. Puts less strain on all the other bearings. Radi pointed out a cool tip. After it might have been slipping, (voltage has been low), see if the Alt. pulley is hot. I want to go back and loosen it a tad now.

CrawdadSlim

Yeah the old soap on the belt is tried and trued. But if you have no idea of the age of your belt and hoses change em out.