Another Stupid Belt Question

I replace the serp belt and it is quiet for about 3 months before it starts to squeal again. It has new AC Delco pro tensioner and idler, new power steering pump, newer upgraded alternator (cs144 with appropriate belt) cleaned all pulleys with wire brush.

I put a bar of soap on the belt edges, and no change. I touch the soap to the back (smooth) side and no change. I touch the soap to the grooves and it goes away, instantaneously.

Here is my question:
Since the squeal goes away when I lightly touch the grooved side of the belt, does this mean it is belt related? Should I continue looking at mechanical? I am using a Gates belt.

I looked for the Green "Fleet" type belt, the expensive one, but could not find it for my application with the CS144.

1996 GMC K2500 with 5.7l, 8 lug,14 bolt SF, 260K miles

I have read through the other posts, but no joy. Still squeals. A new Gates belt makes it quiet for abut 3 months before it starts to come back. (replaced under warranty)

Stumped.

Thanks,

Is anything at all leaking? Power steering, coolant, even a tiny little bit, where it may be getting on the belt by dripping/spraying onto it or getting onto a pulley?

Are any of the pulleys painted and the paint is deteriorating?

Even if say you changed the water pump, radiator, heater hose, etc. and spilled some coolant on the pulleys...

Assuming the tensioner is good and belt tension is correct, what you're describing sounds all the world like a contaminated belt.

Richard

That makes sense. I'll check that. It has been a few weeks since I have looked for leaks under the hood. (Weather has been wicked cold, and lots of snow)

If all pulleys and belt are clean and free of oil/coolant, pull the belt and check all pulleys for looseness or wobble. See if they spin smoothly, listening for any grating noises that may indicate bad bearings. The goal is to spot a pulley that is slightly shifting and causing a misalignment.

Does the noise change when the a/c clutch engages?

You can use a piece of water or heater hose to create a makeshift stethoscope, listening at each pulley to see if you can isolate the source. They also make inexpensive mechanics stethoscopes for that purpose.

These kinds of things can be annoying, hope you find the source.


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Inspect your pulleys and see if any of the grooves are shiny all at the bottom of the groove. If so, it's worn out and the belt isn't being gripped properly by the individual V's in the pulley. If they all look good, clean them thoroughly and use either a light coat of spray paint or a paint pen and cover the grooves completely. Run the engine for a bit and see what sort of wear pattern emerges. If the paint is worn off the bottom of the grooves, the pulley is worn out and should be replaced.

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Thanks All.

I checked the alignment with a straight edge (as best I could anyway), watched the belt on each pulley to see if it was tracking true, and all looks good.

So belt contamination likely suspect.
Contamination Remedy Phase 1:
I went down to the diy car wash and used the pressure wand on the "Rinse" setting and with the engine running, sprayed the grooved side of the belt as it spun and the grooved pulleys. After the water slung off and the belt started drying out, it squealed like a pig, 3x louder than before.

Contamination Remedy Phase 2:
Removed belt and washed it with dish soap and nylon scrub brush. After cleaning, I noticed some debris in spots in the grooves. Brushed grooves with wire brush.
Wire brushed all pulleys (very well)(. For the CS pulley, with belt removed, I started the engine and put the wire brush against the pulley as it spun.

I now have a quiet belt!
I will see how long this lasts, and try to find root cause of the contamination. I don't see any cooling leaks, oil, trans, or power steering leaks.
I do have a front axle seal that leaks. (I think I overfilled it) It looks feasible that some of that oil is being slung in the vicinity of the belt. It is kind of a long shot, but that is the only leak I see.

Thanks again for leading me to the contamination issue.

If this doesn't last, then I will look at the pulleys being worn (thanks SAATR, btw, Atlas Shrugged was a great book.)

Glad to see that you figured this out, and fixed the problem. If I ever have this same problem, I'll have a good idea of how to solve it. Hopefully, it's fixed for good, eh?

No Joy. Squeak came back. Gonna look into changing some pulleys. Not sure which one to start with, though. Will look at each one closely this coming weekend to see if I can identify one that looks different from the rest. Hopefully it is one pulley causing the issues.
Thanks for the guidance.