Noisy belt pullies

Hi,
I've got squeaky belt pullies on the td5, which when I spray with WD40 disappear momentarily. Can anyone suggest a long term solution please?

Thanks, Clive.

If you look closely you will see one of the pulleys (normally the tensioner ) is not running in line with all the other pulleys, this causes the belt to run slightly sideways, then it skips back and so on this happens many time a second and is what makes the squeak.
A good sign is the polished bit of the tensioner pulley is normally wider than the belt itself, but not always.
The wd40 is just acting as a lube so when it jumps back it does it quietly.

Also worth checking everything else is tight and secure as you could have an a/c pump or an idler pulley bearing on its way out.

Assuming its just the tensioner you will need a new one and a new belt to suit, neither is mega dear.

Belts have personalities of their own. Some are squeakier than others. I've got a really expensive one on at the moment and there's a bit of a squeak on start up, whereas the cheaper one it replaced was relatively quiet. It's also worth checking, if it's a multi-vee flat belt, that it isn't running in a skew; that it's in the same grooves on all the grooved pulleys so it's running straight. It can be easy to get it one groove out on one of the pulleys in which case it can shorten the belt life and give you more noise.

belt off and give the pullys a good clean wire brush etc

Thanks all, I'll give it a whirl.

...or put a penny under the tensioner seat to set the correct alignment.

Dirt or contamination of the belt, particularly anti-freeze, can cause screeching sounds similar to knackered bearings.
Take the belt off and give it a good clean in the grooves of the multi-vees and clean the grooves in the pulleys.

Clive jones said:

Thanks all, I'll give it a whirl.

Click to expand...

When my aux belt, on my 300Tdi, developed an annoying little squeak I tried the penny trick, etc. Tried the penny in different positions, but it didn't solve it. I was using a new Dayco belt. In fact I bought a couple. With a new belt it would be ok for a few days and then go back to squeaking. As has been said, if the pulley wheels are not running perfectly true with each other then the belt gets 'corrected' as it moves from one to another. When the belt slides across the smooth pulley it squeaks. The Dayco belts are very soft and rubbery on the back, this gives them a lot of grip on the smooth pulley wheel and so you get a very good squeak when it slides. I moved to a Gates belt, they have a much harder compound on the back, so don't get such a good grip, so don't squeak. Didn't for me anyway and hasn't since.