Pulley noise....

[Ruger]

I noticed since I got my Cherokee, that there was a chirping noise while running. Try to get other stuff done,. I finally checked it.
I pulled my belt, and spun each pulley manually. No noise.. Go figure....:rolleye0012:
I put the belt back on, started her up. Back again!
I got PB blast and sprayed the back of the pulleys.
When I do spray the one pulley is stops briefly, then slowly goes back to chirping again. I guess thats the one. The odd thing is. I don't know what the pulley is called. Its not the little one, I guess the idler puller.
Its the one farthest to the passenger side, looks like there is supposed to be A/C there if you had that option, which mine didn't come with A/C. It's a larger pulley. Anyone know what thats called? And is this common?

[NW99XJ]

On the 4.0L Engines with NO AC there are TWO idler pulleys,
These diagrams shows the two different configurations (bottom shows no AC version) of the serpentine belt routing.
http://ww2.justanswer.com/uploads/brownjeff/2010-06-03_194946_9.gif

http://ww2.justanswer.com/uploads/brownjeff/2010-06-03_195035_8.gif

These pulleys obviously ride on bearings, and in your case, the bearing might be going out. I dont think that bearing is serviceable, so the whole pulley may have to be replaced. Should be pretty inexpensive, especially if you pull one from a junk yard.

[Ruger]

On the 4.0L Engines with NO AC there are TWO idler pulleys,
This diagram shows the two different configurations (bottom) of the serpentine belt routing. (sorry its a bit fuzzy)
http://www.2carpros.com/forum/automotive_pictures/192750_SerpentineBelt92CherokeeFig01_1.jpg

These pulleys obviously ride on bearings, and in your case, the bearing might be going out. I dont think that bearing is serviceable, so the whole pulley may have to be replaced. Should be pretty inexpensive, especially if you pull one from a junk yard.

It would be the large idler pulley then. I think A/C would have been there. I will try my one little junkyard. If they don't have it, I will try my parts stores.
Hopefully not a dealer item.

[NW99XJ]

Quadratec has idler pulleys from 13-about 30 dollars....
So even new they're gonna be pretty cheap.
Good luck.
OH..... And you might as well replace the belt while your at it..... keep the old one as a trail spare.