Thread: Belt Squeal - What is it?

It could be the bearing on the adjuster or idler pulley.
If one of them isn't rotating the belt will slip over them giving off the sound.
Worst case is one seizes while your driving and burns through the belt.
As it snaps the harmonic balancer then tears the rubber creating an even bigger hole in your wallet.
Also check the fan hub bearing while your investigating.

I had an adjuster pulley chirping on shut down.
It had one slightly notchy spot when rotated slowly.


Similar chirping noises have been posted from 2 other areas also.
-A exhaust manifold gasket leak.
This is usually a result of 1 or more studs braking.
-Front tail shaft universals or cardan joint ball.
This will only happen once your moving.

Check simple things first. Belt slip / Check belt for tightness.

Then investigate as Alien said

Gary

Squeal is caused by 1 of 2 things either a bearing is telling you to replace it or one of the tensioner's is slightly out alignment until it gets some warmth

As you stated by the switching off of the AC i would go look there first

Dose the AC run a seperate belt like the TDI300 ? If so get your 1/2 drive or could be 3/8 drive ratchet and stick it in the square hole in the tensioner to take the weight off the belt and give the pulley a spin to see how it feels
This bearing may well be the squealer
If it feels suspect replace the bearing in the pulley if not next step is to lubricate the belt with water
Spray the belt with a little bit of water from a spray bottle this will give the belt enough lube to stop the squeal for a short time start the motor and see if the squeal is there if so squirt the belt again and see if it goes away and even give the main belt a squirt to see if it shuts up
The water trick is the quickest way to tell you that the tensioner is out of alingment and causing the squeal if the water makes it stop if the water dont work you need to look at the bearings

Hope that helps

Originally Posted by alien

Similar chirping noises have been posted from 2 other areas also.
-A exhaust manifold gasket leak.
This is usually a result of 1 or more studs braking.
-Front tail shaft universals or cardan joint ball.
This will only happen once your moving.

Its not the front shaft, and its not the exhaust manifold....been there done that....for both.

I only replaced the idler/tension assembly about 10-15k km ago....but will check that.

I have a new ( genuine) tensioner going in today for the exact reason. It's replacing a non genuine one that was noisy from the get go about 1,000klm ago. I also previously installed a new idler, water pump & belt ( tried 2) My aircon won't kick in, so that's not a factor.

I had a failing Harmonic Balancer causing belt squeal.