Metalic sound from around aux belt

**MFTM** · 01-04-2010,06:41 PM

Hi
I'm after a bit of advice I have a 2003 A4 avant 130 tdi. When at tick over you can hear a slight metallic noise from around the aux belt area it sounds a bit like a chirping noise. When you rev the noise goes away I Have taken the tension of the belt and I can turn alternator and tension pully ok.
Last year I had cam belt water pump and cam belt tensioner replaced so it shouldn't be from there
any advice or simular problems please
Thanks MFTM

**mikeybutch** · 01-04-2010,08:40 PM

Could be a pulley failing or cracked and it may be best to have a close look before it gives up and causes damage .I think its advisable to change all the belts and have pulleys checked when the cam belt is done.Whats the mileage?

**MFTM** · 01-04-2010,08:46 PM

Only 72000. do you know if they are clutch bearing pullys

**way318** · 01-04-2010,10:40 PM

As far as I know the only one that has a clutch in the pulley is the alternator one.

**MFTM** · 02-04-2010,09:30 PM

should all alternator pulleys on audi be one directional as i can turn mine both ways ?

**avanttdi** · 04-04-2010,09:24 PM

sounds like you have a dry or rough bearing on one of your front pulleys, can often be difficult to track down. could also be the belt slipping, that can sometimes chirp. Try silicone spray on the belt (if this cures it then get a new belt fitted and check the tensioner is not seized)
if the silicone spray had no effect, then as mentioned previously more than likely a pulley, take your pick at which one. Best way to check is take belt off and spin them but you cant allways tell, sometimes a stethoscope or the old screwdriver to ear trick can help (with the engine running)

hope this helps

**Something Good** · 06-04-2010,09:06 AM

I had this on mine and thought it was the water pump (which I had changed with the cam belt) - Turned out to be the air con crompressor clutch, which comes as a complete unit with compressor. £3k later and we're sorted!

**Props Forward** · 06-04-2010,09:34 AM

Probably the alternator clutch pulley, common fault, £100 at a garage to fix.

**Something Good** · 06-04-2010,09:40 AM

The alternator has a clutch? What for?

**Props Forward** · 06-04-2010,09:43 AM

I believe its part of the pulley mechanism... I presume so it can only rotate one way but not sure 100%.

There's alot of info about this on here, I have the same problem but I don't know of any effects if it is not replaced... just sounds awful at low revs! Although not have the a/c in econ mode does help!!