Why do belts squeel?

Maintenance/Repairs
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1

On my dad’s car, his serpentine belt will make that loud squeel sound. It does it when you start the car and will do it from time to time while driving. What causes a belt to do that and what can you do to stop it?

2

It’s slipping. The root cause will most likely be a stretched. glazed belt, a tired tensioner, or both. The squeal may actually even be coming from the tensioner itself.

In some cases it can be from one of the belt-driven components (like the alternator) having a bad bearing, but start with the belt and tensioner.

3

Perhaps it’s time to replace the belt…As they wear, they lose their grip. What you hear is the belt slipping on a loaded pulley, probably the alternator…When you replace the belt, you can check ALL the pulley’s by spinning them with your hand…

4

On a $450 car, belts squealing is no surprise. It’s like creaking joints in old people. Here are some reasons belts squeal:

  1. Pulleys are misaligned

  2. Belt is not tight enough and slips.

  3. One of the driven items, such as water pump, alternator is failing and the belt slips over the stuck pullyey

  4. There is water or dirt on the belt

  5. If a power steering belt, the problems with the rack may result in excessive pressure on the pump, causing it to slip.

  6. The belt is wearing out, fraying or “glazed”

  7. The belt tensioner is failing, and won’t rotate.

Other poster can add more causes, no doubt

5

Except that squealing belts are easier to fix than creaky joints…

6

I don’t know that replacement is easier, but recovery from auto surgery is tons easier than joint surgery - and a lot less expensive.

7

I watched a PBS special on hip replacement once. They actually cut the bone, drill holes, and hammer spikes on the ends of the replacement ball & socket joint into the bone…using what looks very much like the 3 pound sledge in my toolbox. They were not gentle. The process may have improved since then, perhaps they use bonding technologies now, but I gotta tell you…that replacement process was 1000 times tougher than any belt replacement EVER.

Happy holidays.

8

Yes, my late brother in law had two hip joints replaced. Very painful and long recovery. Even with good health care coverage, it was no picnick.