Squealing noise from engine when idling

**scubadave** · 27-03-2012,10:42 PM

Have a 130 tdi, auto tiptronic box estate.
Noise only happens on start up and disappears when you pull off.
Any ideas guys??

**Crasher** · 27-03-2012,11:33 PM

Possibly a failing alternator pulley clutch but a little difficult to diagnose without hearing it.

**scubadave** · 28-03-2012,06:16 AM

had a new alternator about 3 weeks ago - not sure if that rules the pulley clutch out?

**Crasher** · 28-03-2012,11:16 AM

Depends if the alternator came with a new pulley or not or it came with a solid pulley which I have seen and is wrong.

**caldirun** · 28-03-2012,08:59 PM

Has the pulley got a black plastic cap on it? if not its solid and that's why you are getting a squeal, it will wreck the tensioner very soon.
Why did you have a new alternator fitted, did you have "Alternator Workshop" warning, if so this could be caused by the pulley seizing, if only the alternator was changed pulley will still be a problem.

**Crasher** · 28-03-2012,11:12 PM

Yes, good point, it looks like this, not open with a visible nut.

**scubadave** · 29-03-2012,09:59 PM

Cheers guys will check it out.
I did get the alternator workshop warning and my battery died on the way to work (after charging the battery all night - had the car booked in for a service the next day, so was trying to leave it till then to get it checked out as had had some false warnings flash up in the few weeks I have owned it and thought this might have been another one!)
Had the new one fitted at a VW dealer.

**caldirun** · 30-03-2012,07:10 AM

I had a few alarms over a week then I had a noise from the front, the pulley had seized, I changed it and it has been fine for the last month, has the pulley got a black plastic cap? Have you checked the tension on the compressor belt?

**Mike McKinstry** · 01-04-2012,09:28 AM

Dont underestimate the importance of getting this sorted asap.A seizing pulley could shear off the idle tensioner bolt which will then involve replacing cambelt/tensioners and getting sheared bolt out of the alternator ali casting!

**caldirun** · 01-04-2012,06:11 PM

As Mike posted if it is the alternator pulley sprag clutch seized, the belt can come off and go into the cam-belt pulley on the crank (I am sure I read of this happening) this could wreck the engine!