Squeaking drive belt on a Jeep Cherokee

Squeaking drive belt on a Jeep Cherokee

When we rebuilt Sandy’s XJ after the engine bay fire, we installed a new Gates serpentine belt. The old belt was completely burned up so a new belt was needed no matter what.

When we started it up, there was a squeak in the belt. I took the belt off and spun all the pulleys. The idler pulley had a nasty sounding bearing, so we got a new pulley and bearing. The squeak came back after a few days.

On a return trip to the shop, I listened to all the pulleys with a stethoscope and noticed a noise in the AC clutch. Since she has not yet bought an AC condenser, I simply swapped her compressor with one I had in the shop. The compressor was bad but the clutch was still good. I had planned to install a new clutch bearing on her at a later date when she was ready to have the AC repaired.

The squeak came back the next day. I let her drive it for a while to see if it would get worse or go away. It got worse.

Back at the shop, I again removed the belt and spun all the pulleys. I even briefly ran the engine with no belt to make sure it was not the damper rubbing the cover. All the pulleys sounded fine on the stethoscope but the squeak was quite annoying. Jennifer asked if it might be the belt.

I found a used but still good belt in the shop and slipped it on for a test. The squeak was completely gone. I drove it for a day to make sure it did not return as it has in the past. On the second day, it is still quiet.

I am not sure why the new belt squeaks. I plan to try it on another XJ sometime to see if it squeaks there. But for now she has a quiet engine again.