The Stovebolt Site Forums The Shop Area Engine Shop Squealing fan belt

The fan belt on my '66 squeals at no matter what, when the engine goes about about 3300RPMs. Even when I tighten the belt or loosen it, it always squeals at the same rpms. I only have 3 pulleys on the belt and I assume that the large distance that the belt travels causes the squealing. I tried Gunk, it doesn't help at all. My fan belt is the V-type (or whatever it is called) that has more traction. Any ideas? Maybe a wide pulley set? Here is a photo, if that helps anything. Thanks

I would check your water pump and generator/alternator bearings, it sounds like something is siezing up.

Dellman,

While V-belts can and do get glazed and loose their traction (permanently) it sure looks like your alternator is maxed out on the tension. How about one size smaller on the belt length...would that allow you to tension it properly.

If the belt has slipped long enough it cooks the friction surface and no amount of tension will save it. Things like Gunk can harden it too so it slips.

I sure would try a new, shorter belt and be sure to tension it properly. After a hundred miles or so, it will stretch and you will need to give it another oink.

Stuart

The possibility of bad bearings on the water pump is possible, it has sometimes made noises before although it spins easily when spun by hand. But I will try atomarc's suggestions, I don't think it is a warn belt as I had bought another one in attempt to fix the squeal and it did not help. The belt tension is maxed out so I will buy the next size down sized belt probably tomorrow, I will let you know the results. Thanks

Also, very carefully check the alignment of the pullies with each other. Even a small offset can cause a belt to squeal.

Dellman,

It wouldn't hurt to clean the grooves on the crank and waterpump pulleys either. Brake-Kleen and a little sandpaper will give them a good new surface for the belt to bite on.

Stuart

Stuarts suggestion might help, but I've found that older high mount position is very prone to squealing with an alternator, it may be the long travel .... prolly why they changed later to the low mount with shorter belts

Bill

try wiggling the fan blades fore and aft there should be no play...
if there is the waterpump bearings are on their way out....
any spray on belt conditioner is short term fix and contamination, either oil or antifreeze will cause noisy belts also if the belt is too tight it will cause noise....pressing down moderatly on the
middle of the belt between pulleys you should have 1/2-3/4" deflection only.

get you a long wooden stick and probe around the alt or where you might hear the noise...you can pick up the noise real quick.. just stay out of the moving belts..

Looks to me from your picture that you're running too wide of a belt for the pulley grooves. The belt should set down flush with the top of the pulley while yours is sticking up past the edge.

If that's a 1/2" wide belt you're running I'd go with a 3/8 Gatorback and get rid of the belt dressing.....that stuff will kill a belt in a heartbeat. The Gatorback belts are a little more expensive but when you get the correct width and loose the squeal it will seem worth it!

Dave

I bought the next size down fan belt. I checked the bearings on the water pump and made sure that the pulleys were lined up. Next I clean all the old burnt rubber surface from the pulleys and installed the belt. The squeal is completely gone, even at 5,000rpms (high as I wanted to go). The problem is solved even though the alternator is very close to the valve cover now; I had to remove the cover to install the belt. Fla54Chevy3100, I noticed that the belt seemed too wide but I didn't read your post until after I bought the new belt but the squeal is gone now anyway. Anyway, thanks everyone for your help!