Terrible squealing with A/C on?

Until the engine heats up to around standard operating temp. anyways.

Im thinking the pulley/clutch on the A/C unit is bad, but Im not quite sure, as this is my first vehicle with A/C :yap: (drove a TJ without it for years)

Could this have any effect on gas mileage? Mine is currently getting around 11 in the city, and I feel this is WAY too low (don't usually run A/C though, usually keep the windows down)

Disable the a/c clutch and see what you get.

Pull the belt, spin all of the accessories by hand checking for roughness of failing bearings. Exam the belt, replace if necessary--Goodyear Gatorback is good.

JP Magazine did a three part series on XJ mileage--Project Mileage Master I believe was its title, hit jpmagazine.com and search. They had a huge mileage drop with a bad PS pump.

When was the last time you checked the belt tension? (It's not automatic) For that matter, how old is the belt? If it only squeals when cold, try tightening the belt tensioner a turn and see if it stops.

tbburg said:

When was the last time you checked the belt tension? (It's not automatic) For that matter, how old is the belt? If it only squeals when cold, try tightening the belt tensioner a turn and see if it stops.

Click to expand...

That is what we believe it might be. As to how old the belt is, no idea. It looks fine though.

Where can I find the tensioner? Ive got a haynes manual but its not with me ATM.

What year Cherokee? I think the early models are different. On the late models, there is a lock bolt and a jack screw bolt behind/below the PS pump. You loosen the lock bolt(from the front) and turn the jack screw to loosen/tighten from the top. Memory says 14mm, but memory around here isn't known for accuracy.

Its a 99, so Id guess its the lock bolt on the PS pump then...