I got a squeaking belt... How to diagnose?

[ShooterMcGavin]

Hey all. I changed out all my accessory belts a while ago and tightened things up the best I could. None of the belts feel loose. I have had other mechanic friends look at it and they say all belts seem tight enough. Nothing squeaks during normal driving but, when I put my foot on the gas hard, a belt squeaks. I've heard that you can diagnose/stop a squeaking belt by spraying it with water...

How do I spray only one belt with water when they are so close to each other? Spraying it while it's on is the way to get it fully covered, but how do I do that with the fan trying to eat my fingers? Other advise for solving this issue?

It's not a critical issue but, now that I'm towing a small trailer regularly, it's getting annoying.

 

[kolelt]

Sounds like the alternator belt isn’t tight enough

 

[TheDurk]

Water is hit or miss. If the squeal is a loose belt, the slippage will normally occur at the driven component: the alt., the P/S pump, or the A/C compressor.

Don't worry about A/C, because that will normally only occur when A/C button is pushed, so it gives itself away.

You can spray those other two pulleys without too much risk to your extremities. If that doesn't work, then your problem may not be a belt. Squeal could be from an idler or from the driven component itself. You can try a mechanic's stethoscope but it's tough to reach some components.

if that doesn't work, then it's time for the nuclear option. Remove all the belts. Check all components and idlers for sticking or excessive play. If all appears normal, replace belts one by one until you isolate the one that squeals. Or just replace all the belts while you are at it, if they are old enough to justify it. You still want to go belt by belt to rule out idlers and components.

 

[LittleCaesar]

How do the pulleys look? Any rust? I had a pulley on a friend's older Camry build up a little rust burr on it which would catch the new belt and make it squeal. Some soap/water and a brass brush should take care of it, if that is the case.

I would just tighten up the PS and ALT belts one half tensioner turn and see if that helps first.

 

[ShooterMcGavin]

Thanks guys. From memory, I don't think there is rust on the pulleys for the accessories. The idler shouldn't be making noise since it was brand new with the belts - also did the timing belt with the accessory belts. But it could be faulty I suppose.

When I do the one-belt-at-a-time option, I need to remove the fan and 2 other belts, reinstall everything and test, and then do it all again? It sounds like a long option, but I'm sure it's concrete in diagnosing. I'm avoiding doing that. I'll probably just tolerate the squeak before I do that.

If I have AC turned off, were you saying that the belt absolutely won't squeak... I assume because it is not being engaged?

 

[TheDurk]

Thanks guys. From memory, I don't think there is rust on the pulleys for the accessories. The idler shouldn't be making noise since it was brand new with the belts - also did the timing belt with the accessory belts. But it could be faulty I suppose.

When I do the one-belt-at-a-time option, I need to remove the fan and 2 other belts, reinstall everything and test, and then do it all again? It sounds like a long option, but I'm sure it's concrete in diagnosing. I'm avoiding doing that. I'll probably just tolerate the squeak before I do that.

If I have AC turned off, were you saying that the belt absolutely won't squeak... I assume because it is not being engaged?

Absolutely, no. But it has to be pretty loose. It squeals because it slips. It slips because the driven pulley resists the pressure of the belt turning it. A/c off, it doesn't resist very much.

As to the one-at a time, if you can't identify the problem, you will want to pull all the belts so you can check all the pulleys for play or roughness with the belts off. Then, you just reinstall them one-at a time and test after each one. You don't test each one in isolation. It's test 1, test 1&2, test 1,2&3. There is a sequence you have to follow anyway.

 

[ShooterMcGavin]

Got it. Thanks for that!

 

[LittleCaesar]

Or the belt could just have been bad out of the box. Are they OEM?

My guess though is the PS or ALT is just a little loose.

 

[TheDurk]

Or the belt could just have been bad out of the box. Are they OEM?

My guess though is the PS or ALT is just a little loose.

Has that ever happened? How? Belts wear out over time and lose the ability to grip the pulleys as the surface wears down. Lots of things are bad out of the box from time to time (Bosch parts = more often) , but I have never seen it with belts, although I suppose getting the wrong size is possible.

 

[LittleCaesar]

Has that ever happened? How? Belts wear out over time and lose the ability to grip the pulleys as the surface wears down. Lots of things are bad out of the box from time to time (Bosch parts = more often) , but I have never seen it with belts, although I suppose getting the wrong size is possible.

I can't say Durk how the weather is in NJ year round, though I have been there many times (used to have relatives in Sea Bright). Belts here in the South, if exposed to serious cycling of weather (extreme cold, then hot and humid) can deteriorate, even if they are just sitting in inventory, being in an environment that is climate controlled or not. In 20 years I have probably returned close to a dozen that were new, but had been sitting for some time. Dayco belts, for me at least, are the worst. Had two new ones split on me by just adding tension.

Ditto for rubber hoses as well.

The one thing not found here in the South is terrible rust....:spy:

 

[TheDurk]

I can't say Durk how the weather is in NJ year round, though I have been there many times (used to have relatives in Sea Bright). Belts here in the South, if exposed to serious cycling of weather (extreme cold, then hot and humid) can deteriorate, even if they are just sitting in inventory, being in an environment that is climate controlled or not. In 20 years I have probably returned close to a dozen that were new, but had been sitting for some time. Dayco belts, for me at least, are the worst. Had two new ones split on me by just adding tension.

Ditto for rubber hoses as well.

The one thing not found here in the South is terrible rust....:spy:

Fair enough. I have only used one NAPA store for belts since the 70s, or got them online. I only use NAPA, Gates or OEM. But yeah, let them cook long enough in inventory you will kill them.

 

[ShooterMcGavin]

Or the belt could just have been bad out of the box. Are they OEM?

My guess though is the PS or ALT is just a little loose.

I'm not sure if they are OEM, but I doubt it. I bought 2 sets of belts at the time I did the work. I think these are the belts bought from O'Reilly's.