Thread: Sneaky pulley noise..grrrr!

I had a pulley / belt noise most noticeable on tickover. It drove me crazy trying to sort it. I was convinced it was the air con compressor clutch bearing as I could stop and start the noise with the aircon kicking in. I changed the clutch bearing and still had the noise. The alternator is not very old so discounted that. I then changed the pulley under the power steering, still there. Then the tensioner Pulley, still there, Finally I got to the Idler pulley directly below the alternator, Result noise gone.
The pulley in question is Plastic. The surface had worn down until only a very thin layer was left, I think I put a post up at the time with a warning.
The new pulley is a nice chunk of steel.



I just found this Picture of a failed pulley, mine was still intact but as you can see the surface wears away and its not clear until BANG. Maybe not your issue but I would look there anyway.


Have a read, if yours proves the same maybe post again with a general warning........
http://www.aulro.com/afvb/p38a-range...lternator.html

I like the look of the bogan battery cover

Gary

Originally Posted by mtb_gary

I like the look of the bogan battery cover

Gary

Can I please clear this up before it gets out of hand and rumers start to spread, Thats not my car, Not my battery cover, I have never owned a Lumberjack shirt and never will.
( No offence to lumberjack shirt fans)

Thanks for sharing that Wayneg, great photo too!
I might get under there again tomorrow, pull the belt back off and check that pulley.
I know sometimes these things become a process of elimination, but that is a good start.
Will let you know how I go.

Originally Posted by PeterH

Thanks for sharing that Wayneg, great photo too!
I might get under there again tomorrow, pull the belt back off and check that pulley.
I know sometimes these things become a process of elimination, but that is a good start.
Will let you know how I go.

Just an add, I looked at the pulley at the start and it seemed fine, at least the bearing was not noisy. Now I know the surface should be flat right across the belt contact surface. If you have ridges at the edges thats the sign of wear, I presume the plastic becomes so thin it starts to flex

OK, the noise is getting a bit worse today, and still only does it during driving.
When at idle there is no unusual sound at all, which is a bit frustrating to say the least!
I let the tension off the belt, checked all the pulleys and every one turned freely without any noise.
The idler pulleys are both metal ones and I could not detect any problems with those.
I did notice a 1mm movement when I pulled on the steering pump pulley, and in and out movement rather than a side to side movement. The pulley spins freely though, with no noise nor roughness at all.
There was also a very slight movement of the fan via the viscous coupling, but it seems to be working fine.
The sound has develpoed into what sounds like a chirping belt, sometimes catching, like a metallic clunk.
I'm wondering if I'm on the right track, maybe it's something else, but so hard to tell as it only happens while driving.
Anything I'm missing here?
Thanks, Pete.

PM sent

If you turn the aircon on, when the compressor is running you will put additional load on the belt, does that force the noise to start? Also recall someone had the power steering pump pulley work loose
http://www.aulro.com/afvb/p38a-range...bolt-thor.html