noisy fan belt

[witt]

......I am stumped: Low, loud hum coming from fanbelt.......tried lose and tight and correct adjustments.......tried my spare belt.....no change....here is the part that gets me: spraying WD40 into the gove of the lower pulley eliminates the noise for a minute or so, same when spraying on the belt. The belt is one year old with minimal milage and shows no damage ! Just had the alternator out, tested and a new regulator installed to fix a charging warning light problem. The noise happened before that repair, just got slowly louder over time. No noise if motor runs without belt, alternator rotates freely.
Now, what ??? Any help would be greatly appreciated.

CHEERS !
WITT !

PS: Belt size, Conti - SF - AVX10 X 710 LA

[dshepp806]

bearings? OK?

Doyle

[Reiver]

Clean the pulleys. Is the fan a 9.5 mm wide or a 10 mm. You might try a dif width fan and it will ride at a dif height than the present one.

[mpetry]

I just had a similar problem, same belt (conti 710) checked the alternator bearings, all smooth - I think it was the cold weather - just a squealing of the rubber on cold metal.

On another car I applied belt "dressing" and the result was... noise!

I think the rubber gets sticky in cold weather.

[Reiver]

Cold weather everything shrinks = a tad looser than normal so that could be it but I'd clean everything up as I had old gunk between the shims (finger applied old grease) that made fine adjusting dif...and clean the pulley races too. If it still makes noise try another width then readjust the play.
I had a similar issue the other day (finally got an Az freeze) and cleaning / retorquing everything got rid of the issue (mine was a squeel and humming).

[DRACO A5OG]

make sure your crankshaft pulley is tight. this is a common neglected item, if ignored, you will damage the seal or worse the pulley and most likely the #8 bearing

[DRACO A5OG]

pag belt 3 in 3 out on the shims
conti belt 1 in 5 out.

[witt]

.....thank you for all the advise, but I may have given some misinformation: the fan is "houling" not humming........The noise disappeares when I spray WD40 on any part of the belt, so its got to be the belt ?!........after a few minutes of idling the adjusting hardware on the fan/top pulley gets to hot to touch, is that normal ?......is a certain amount of noise acceptable? ......mine is screaming now......the alternator was removed and tested and is rotating freely......my next step is to experiment with different types of belts...... wish me luck.......will report back !

CHEERS !
WITT !

[pete3799]

Your fan belt is slipping on the pulley causing it to get hot.
Spraying WD 40 on it makes it slip worse you just can't hear it slipping anymore.
Your fan belt is now junk (from spraying oil on it).....get a new one and tension it correctly.

[witt]

.....latest up-date: I cleaned everthing that the belt touches, "spick und auch span", and installed a new one, no change. However they sold me a 11 X 710, but I tried my spare conti 10 X 710 with no change in the noise. It's a deep loud humm that started in the fall and got worse. ( being a spare it is not worn but just old ) Having a hard time finding a new conti 10 X 710 but will keep on searching. Maybe the cold weather has something to do with it ?!

CHEERS !
WITT !

PS: I stopped spraying WD40 on the belt.

[witt]

Lates update: Found and installed correct brand new Conty belt, cleaned everything that comes in contact with the belt, adusted it to specs.....no go !
The humming / wining noise is louder than the motor ! ! ! That cant' be right. It is so bad that it puts me off driving the car. Any thoughts, anybody ?

CHEERS !
WITT !

[Jonathan S]

Sounds like you are your WITT's end?

I had a similar problem, replaced the alternator. It think it was the bearing making the noise. The alternator was melted anyway. A howling/humming noise is usually a failed bearing even though it still turns by hand.

Maybe mock up a test for the alternator bearing using a spare pulley on the end of a drill. I am not sure if you can get enough RPM but maybe something like that could at least tell you without having to run the engine.

Jon

[witt]

......interesting thought, come to think of the noise started after I had the alternator out, regulator replaced, unit tested at a reputable shop and I re-installed it. Maybe it does not sit correct, will check that out....what gets me is that spraying WD40 on the belt itself, no where near the pulleys makes the noise disapear for a few seconds......its' a miracle......( I am not spraying on the new belt anymore )

CHEERS !
WITT !

PS:....nice pun, by the way !

[Jerome74911S]

Originally Posted by DRACO A5OG

make sure your crankshaft pulley is tight. this is a common neglected item, if ignored, you will damage the seal or worse the pulley and most likely the #8 bearing

The crank pulley came off while at 6000 rpm in 5th gear at a DE day. My buddies car. He had to do a partial engine drop to repair the sheared pin - missed one 20 minute session.

[witt]

.....by George I GOT IT.....checked the ad by DAYCO belts on this site. They suggested that it may not be the belt but that the pulleys are misaligned. Just for the hell of it I took before and after videos. This is what I did: losened all bolts that hold down the alternator, started the motor and tried to push the alternator back and forwrd a bit: IT WORKED !
.....now that is the official story, what really happened is this: as above, but (kids dont' try this at home ! ) I used a crow bar to move the alternator ever so slightly and.........the bar slipped and hit the running alternator (just a few beauty marks) and the noise stoped. I believe my guarding angel was working overtime and Murphy was gone for lunch.......

a verry happy and lucky
WITT !

PS: how do I upload the video ?

[Joe Bob]

You have to post to You Tube then hotlink back here.

[rusnak]

When the pulleys are not aligned, usually it's because the fan shroud is not installed correctly. The fix is to loosen the hold down strap, and push the fan shroud into position. I think the alternator bolts are better used to center the fan in the shroud.

[vngufmxw]

it will ride at a dif height than the present one.