My XJ would squeak when I would accelerate with the A/C on full blast or when the defrost was on full. I thought it was the serpentine belt so I replaced it leaving about 1/4" tension on the belt ( I don't have a tension gauge" ) Anyways after replacing it I get about a second or two of some moderately squeaks when I first start the car but it still squeals when I pump the gas with the A/C / Defrost on. I'm guessing it's some bad bearings on the compressor or something but I'm also wondering if the squeaks that happen when I start the car can be fixed.

Also it is lie 20 degrees outside if that is also contributing.

Any help on how to get rid of the squeaks on start and how to stop them when I accelerate would be great.

 

i would check all your pulley... just loosen the belt and spin them all by hand... check for any sqeeks or jiggly (technical term) pully's ... the main culprit is usualy the idler pully... witch mounts right next to your ac pump and right below your valve cover (cross your fingers this is the cheapest easiest pully to replace and really common to wear out ) ... good luck.. let us know what it was...

p.s. if it ends up being your a.c. pump and you need a quick fix or don't mind warm summers... just type in cherokee a/c bypass in a google search... they make a bracket/pulley that delete your a/c

 

Turns out it was my idler pulley and it did need some tightening. It doesn't make a sound now but is there any way to tell if the belt is too tight? I'm followed the "for every foot of belt there should be 1/2" tension" but I'm a little paranoid about it being just right. Is there any easy way to tell if it is too tight?

 

The rule of thumb I've used is... you should be able to twist it almost 90 degrees by hand.

 

did this fix the squeek at start too?

 

Well it stopped squeeking completely for about a day then whenever I had the heat on and the rear defrost on it would start slipping so I went out and bought a tension gauge and it read 150lbs on my belt so I know it needs to be tighter so I'm planning on doing that tomorrow I'll update.

 

you know i've never been so precise with a belt... i didn't even know there was a tool to read it... never had any problems (with the belt of course)

 

Yeah normally I wouldnt mind but I really dont want to screw up those bearings. I tightened the thing again and everything checks out. It is normal for the batery meter on the dash to drop a little if I turn on a lot of accessoroies while the engine is idling right?

 

Mine did that too, i left about a 1/4 slack in the belt. I just tightened it till it stopped, problem solved. Works like a champ, even when wet.

 

The problem is the bearing on your AC pulley. They fail and squeal when the compressor kicks on. There's a guy on Feebay who sells replacements for around $18 I did it on mine and now all is well and quiet.
here is one

 

mine used to squeek with the air on and when giving it gas... i thought it was the fan clutch... but replacing that didn't fix it so next i just replaced the belt i wasn't precise at all i just put the tensioner in the place it was before, that was over the summer and i haven't had any problems since