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Frank Lee 09-06-2009 03:34 AM

Serpentine belt squealing- I might have some good advice
I went through a semi-enclosed drive-thru the other day (Yes, I know! Bad!) and was astonished at how noisy the serpentine belt had become on my 15 year-old ride. Come to think of it, pretty girls had been looking at me strangely when I drove by. Hmph. Thought it was me. Time to take action.

Got the stethoscope out (a piece of fuel line) and with the engine idling and while being hyper-aware of the rotating parts, I isolated the alternator as the culprit.

Took the belt off and gave the alternator a whirl by hand. Hmmm. Sounded OK. :confused: Well I decided it was so easy for me to remove it and have it bench tested that that is what I'd do. It tested fine.

Many years ago this rig squealed too. That time it was dry idler and tensioner pulley bearings. Stupid vendor was chintzy with the grease! A normal person would have replaced them right? Well I found a small syringe, loaded it with grease, and was able to work the tip under the seal lips and load 'em up good. They still sound like new. :thumbup:

Back to today: All the rotating bits were good and the everything passed visual inspection too. So what th'? I thought, maybe it's dusty/dirty/greasy enough to squeak? Made a nice strong batch of hot soapy Dawn water and scrubbed the belt and pulleys down. Rinse, dry, install... no change.

I gots online and found tons and tons of bad advice- throw new parts at it, fool around with shims, put belt dressing on it, put GREASE on it?!? :eek: :mad: But then I found a page that made sense: after eliminating all other causes, the pulleys and belt are probably GLAZED.

Glazed? But I already inspected it all! Can't be! With nothing to lose I got out the wire brush and brushed the belt down (heh heh, you didn't think I'd listen to the page and go get a new one?!?) and all the pulleys too (except portions of the main drive pulley on the crank that were too hard to reach). Since there was a good chance my brush had oily residue on it I cleaned everything up with brake cleaner.

Voila! Success! This old dog learned a new trick. Glazing on V-belts is easy to see but I simply couldn't tell by visual means on the serpentine belt and pulleys. If you're having a tough time silencing a noisy belt system this might be the ticket.

Christ 09-06-2009 12:12 PM

The only time I've ever thought of brushing a belt is to help it get more traction when you first put it on... But I don't ever really replace them, either. ;)

Good piece, Frank.

bgd73 09-06-2009 12:35 PM

that is advice I haven't used in some time.
I wander back a few 15 years and realize the sube double belted has one used one going on 185k without a change. I never ever call anything that lasts overdone, but the old sube does something amazing there with the thick v-belts paired together.

The serpentine is yet another modern frustration. its like getting 24 inch rims for a half inch of hemmorhoid making tread, its like glass called safe-lite in a unibody that had 5mm original, it's like winter wiper blades flying off into the wind...

its like calling steel 17 guage after 4 layers of paint...

its like brembos on a 1 ton car...

the serpentine belt is the electric fan that doesn't kick on....

and then call it all efficent. :confused:

mikeross 03-04-2010 04:08 AM

How do I stop the serpentine belt from squealing? My belt was just replaced and it still has a slight squeal to it! I've heard that you can lubricate the belts slightly! What would be the best formula or lubricant to use? Oil, power steering fluid or what? Thanks.

gone-ot 03-04-2010 08:37 AM

...remember the "trick" of rubbing soap on the sides of a v-belt to stop squealing?

fud2468 03-04-2010 09:45 PM

Brake fluid used to work on v-belts to stop squealing, not sure if it would work on a serpentine belt.

wagonman76 03-05-2010 12:29 PM

Funny you made this thread. The wife has been complaining this past week of the Cavalier belt squealing. Belt dressing silenced it immediately, but didn't last more than a day. I could tell the reverse pulleys were like mirrors and could use a little deglazing, but I didn't think about the belt being glazed. I took a wire brush to the belt and pulleys and no more squeal.

orange4boy 03-06-2010 01:50 PM

One reason for a squealing belt can be a dying or undercharged battery. That's how I got into this whole ecomodding mess. My battery was undercharged and dying so was loading up the alternator on startup. new battery, no squeal.

lightflite 03-08-2010 07:34 AM

This I will try!:D

I have a 10 year old Espace (2.0 lit petrol) with an vast serpentine belt - the noise it makes scares crows at 100 paces. Spray-on lube always instantly stops the noise for about a day or two. Originally I used WD40, but this ate the belt in a year or so.

I now use silicone milk (armor-all) or dabs of (electronic) silicone grease as these can't harm the belt and don't affect the function of any of the driven auxiliaries.

AeroModder 03-08-2010 11:28 AM

Also remember- TENSION!

My v-belt to the alternator was squealing like a banshee, and I thought it was the power steering pump seizing. Nope. It just wasn't enough tension on the v-belt.

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