Belt dressing or WD-40?

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My Buick with the 3.8 has been whistling at me -- a whine on cold startup that lasts for about a minute, then vanishes as (I presume) things warm up. My regular mechanic suggested a quick squirt of WD-40 on the belts and pulleys. The 40 is nice to have around the house, but what about these belt dressing sprays? Any harm possible to modern belts? And should I spritz the belts while the engine is running? Any input welcome!
 
Actually the noise in question didn't make an appearance on stage this morning, so it may be moot.

In any case it would be a temporary fix, until I can get to my regular shop. I mean, if the belt is squeaking, and the spray quiets it, then we know it's most likely a belt, mais non?
 
Belt dressing is a no-no for multiribbed belts. It is only meant for single-vee belts.

If you need to test for squeak, use water, not WD-40.
 
I use WD-40 from time to time to locate such noises. It seems harmless and dissipates fairly quickly without leaving any residue. If you have a serpentine belt on that motor, It's probably due for replacement. My experiance with serpentine belts, (mopar), is that 50% of the time the noise is coming from the ideler/tensioner pully bearing.. YMMV.

Sounds like you have found a keeper. Good luck...
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always against the use of DoubleU-Dee40s on rubber belts for not only will it cause premature deterioriation to the rubber (yes, rubber doesn't like oil-based lubricants).

Instead of resort to quick fixes (which doesn't work properly with serpentine belts anyways), always spend some time looking deeper into the problem and resolve it. Most of the time, the squeaking is an indication of too loose of a belt (if you happened to have the belt replaced recently), greasy pulley surface, seal/bearing problems on belt tensioner, waterpump, alternator, A/C compressor, PwrSteering pump, etc.

If you want to test your belt while your engine is running, try some soapy water instead.
 
Avoid WD40 and the belt sprays. They quiet the belt for a few minutes and its then right back and usually worse than before.

I learned this the hard way many times
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Never put belt dressing or any other lube on a serpintine belt!!!! Belt dressing is ok on old school V belts. I have found that if anything cleaning the belt's and pulley of any grease residue helps when nopthing else does. So start the car up and spray some type of cleaner like Greased Lightning, Fantastic,409,Castrol Super Clean,liquid dish soap mixed 50/50 in an old spray bottle etc...... Spary it right on the belts and pulley with the engine off then start and spray some more. Let this stuff run about 10 seconds then start hoseing off the part's that were sprayed.
 
If coolant has gotten on the belt or pulleys, they will squeak. Sometimes a good scrubbing with some of the cleaners JohnBrowning mentions is all it takes -- along with a new belt. Other times the bearings in one or more of the pulleys are going bad and voicing their complaint. Rotate by hand the parts with the drive belt off and carefully feel for roughness in the bearings, also listen carefully. Sometimes one can feel or hear a bad bearing, other times an electronic listening device (professional mechanic tool) is needed. One should check that all the pulleys are in-line using a straight edge. If the mounts for one of the driven items are miss-aligned the belt will voice its own complaint.
 
Thanks for all the input,

The noise has vanished, all by itself, and the engine runs quietly and smoothly. I'll keep the WD-40 for other things, and skip the belt dressing!
 
I've never used belt dressing- I've always just replaced the belt if it made noise. But something strange happened today.

There's a big exhaust fan way up on the back wall of our shop- probably 20 ft. up. The belt has been squealing non-stop for about a month... and nobody seemed to care. I guess it was driving one old timer nuts. He couldn't find any belt dressing... so he grabbed a can of that Permatex Copper gasket dressing. The old ---- climbed up there and sprayed the belt. It was quiet all day.
 
I would never use WD-40 on any belt, V belt or otherwise. Its a small amount of lubricant and a lot of carrier (which evaporates, but is not good for any belt).

If you have a serpentine belt, then maybe you should check the idler or tennsion pulleys if you have some noise or w whine.
 
I can't recall the exact sequence of events, but it seems the noise *began* after my initial check of the power steering reservoir, and *ended* soon after I topped off the fluid and stopped fooling with it. Possibly a drop or two of PS fluid got on the serpentine belt and made it slip until the stuff wore away?

In any case the sound hasn't come back, so I'm happy with things as they are (my new rule for dealing with cars: "No [unnecessary] fussing") and will check the belt condition as needed.
 
The belt will get a quiet kind of a squeak from time to time. I take and squirt a tiny amount of garage door lube on the harmonic balancer pulley while it's running. Does the trick.

Benzadmiral: does your belt tensioner pulley have a 15mm hex head bolt or is it a Torx head bolt? You're going to want and find out before it's time to change a belt. The bolt is left hand threaded; that way when you push back on the tensioner to slacken the belt for removal, the bolt won't loosen. There should be an illustration of the belt routing in your owner's manual.

By the way, I'd suggest you subscribe to AllData; it's only $25 a year and it can be extremely helpful.

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Originally Posted By: JohnBrowning
Never put belt dressing or any other lube on a serpintine belt!!!! Belt dressing is ok on old school V belts. I have found that if anything cleaning the belt's and pulley of any grease residue helps when nopthing else does. So start the car up and spray some type of cleaner like Greased Lightning, Fantastic,409,Castrol Super Clean,liquid dish soap mixed 50/50 in an old spray bottle etc...... Spary it right on the belts and pulley with the engine off then start and spray some more. Let this stuff run about 10 seconds then start hoseing off the part's that were sprayed.


Exac boat I am in as of today. Had mechanic replace water pump and radiator bypass hose today on my 1989 Bonneville. Put in a new drive belt not 3 months ago when we did the harmonic balancer.

I leave the shop and as I was driving around the block and bringing the RPMS up I started hearing the squeak. Went back and he sprayed it down with Armor All. All good. Until tonight that is. It's back. He admitted he may have got some coolant on the belt when he did the water pump.

I was thinking about just taking it to the car wash as just spraying it off with some soap on low pressure while its running. What do you guys think?
 
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Check out DAYCO's web site...they have a nice tutorial on belt noises and their causes & cures. According to them, many times it's because of build-up in the grooves of the pulleys, which very few people bother to clean when replacing a belt.
 
DO NOT USE BELT DRESSING. That stuff makes a serious mess on serpentine belt systems. Take it from me, I've tried it. The WD-40 is safe and will tell you if you need a new belt or not. If the squeak goes away momentarily right after spraying the belt with the engine running, that tells you you need a new belt.

The other thing that can cause belts to squeak is if the pulleys are out of alignment, but that's rare.
 
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