Thread: Squealing belt

maybe one of the devices driven by the belt is overloading it.

possibilities:

Power steering pump
water pump
AC pump
alternator
really stuffed tensioning idler

the gurus will be onto this and know much better than me, but I'd start looking at these

The common cause is a stuffed tensioner. If a belt lets go then often a pulley gets damaged too.

I have the same problem. I have changed the belt for a new one only to find noise comes back again. I'm starting to lean towards the tensioner or the water pump pulley. Is the water pump pulley supposedspin freely or does it spin and then come to a stop due to internal resistance. The tensioner is fairly new but i am able to push it down about 2 mm easily with thumb pressure when it's cold is this normal? Somebody out there must know as i don't want to waste anymore money if i can help it as i'm sure rad97 feels. Tensioner costs about $160 and water pump is slightly more from memory.

The main problem with squeling is caused by the belt.

Some makers (Dayco) have a smooth finish on the back which in most cases people have a problem. Other makers (Lemforder) have a "rough" finish on the back and problems are non existent.

Hope this helps.

Originally Posted by karcraft1

The main problem with squeling is caused by the belt.

Some makers (Dayco) have a smooth finish on the back which in most cases people have a problem. Other makers (Lemforder) have a "rough" finish on the back and problems are non existent.

Hope this helps.

Yep, I had this when I got the belt changed last year during a service. Took it back in and they changed the brand of belt for one with a more grippy back. All good now. Certainly turns heads when they squeal

Are you sure it's the belt making the noise? Although a squeeling belt is a bit different to a growling bearing.
Anyway, how long is it since you've replaced or regresed the bearings in the idler pulleys?
If you've got a Tdi, there are three bearings - all the same size, only about $7 each and easy to replace, including the one in the tensioner assembly.
The Td5 is a bit different and only has two idler pulleys and each bearing is a different size. Also, the one on the tensioner is held in by the two halves of the pulley being rivited together so is not simple to replace.

However, although they are all (tdi and td5) 'sealed bearings', it is possible to prize the plastic/nylon cover from each side of the bearing, give it a good clean out and repack it with grease - provided you do this on a regular basis before the bearing had run dry and destroyed itself.
I recently gave three Td5's this treatment and each bearing had very little grease in it when inspected. See photos below.

IMHO these bearings should be serviced at least every 100,000kms - and as they say 'more often under severe conditions'. Siesure/failure of these bearings is often the cause of a broken belt.

Tensioner replaced 20000kms ago and i replaced bearing about 5000km ago when first noticed squeal after changing belt. Are the other 2 bearings located behind the alternator pulley and the power steering pulley?

Originally Posted by dhard

I have the same problem. I have changed the belt for a new one only to find noise comes back again. I'm starting to lean towards the tensioner or the water pump pulley. Is the water pump pulley supposed to spin freely or does it spin and then come to a stop due to internal resistance.

Yes that is Correct. it's not supposed to spin freely due to resistance as you said.
The tensioner is fairly new but i am able to push it down about 2 mm easily with thumb pressure when it's cold is this normal? Somebody out there must know as i don't want to waste anymore money if i can help it as i'm sure rad97 feels. Tensioner costs about $160 and water pump is slightly more from memory.

you Can get a non Genuine L/R water Pump from BMI for $97.00