Brief chunking sound and simultaneous belt squeal

MICHAEL TARVER III

MEMBER
1999 JEEP WRANGLER
4.0L
6 CYL
4WD
MANUAL
216,059 MILES

During the cold and now cooler weather when I start the engine, the serpentine belt squeals as though it were loose but at the same time there's a 'chuck-a-chunk-a-chunk' for like maybe two to three seconds. When the chunking sound stops, so does the squealing.
Any ideas?

1 Reply

SCGRANTURISMO

MECHANIC
4,897 POSTS

Hello,

This is probably a pulley on one the components that the serpentine belt is running or an idler pulley or the tensioner. Every component that the serpentine belt drives the powering steering pump, water pump, A/C pump, alternator, supercharger (if equipped) all have input shafts that all have a bearing that makes them turn true. Over time and with normal wear and tear the bearings in the pulleys go bad. They don't fail overnight, instead, fail over a little bit of time, and make all kinds of noises as they are failing to let you know about it. The squealing of the belt is where the bearing is failing it does not want to turn and is turning slower than the rest of the bearings in the pulleys of the other components. Go to the front of your engine and follow the serpentine belt around. Any where it goes around a pulley. Check the pulley to see if there is slop, or play in that pulley. Find the one that has play, you have found the problem. Get back to us with what you find out, please.

Thanks,
Alex
2CarPros