Alternator noise?

John H

John H

Member
My 1.4 TDi (75) has now done 87k miles, and is beginning to develop a subtle new noise. It is a bit of an extra growl, just above idle, and seems to be made worse if I load the electrics (lights, rear screen). The car is otherwise running fine, and was recently serviced.

I suspect that the noise is coming from either the alternator, the belt or the free wheel pulley. It is however sufficiently faint as yet that only an owner's ear would notice it, so I doubt the garage would hear what I am describing.

Any advice?
 
The only practical advice is to keep an ear out for any increase in volume. The pulley/freewheel is changeable, but you'll need a special tool and the parts are around the £45-50 mark from what I can recall.

Cheers,

Mike
 
Thanks for that Mike, sort of what I thought myself.

How robust are the alternators? ... is it coming to the end of its life, or should it run for a while yet, and any idea what they cost if I should have to replace it?
 
The alternators themselves are pretty long-lasting (I've only had mine replaced as there was crash damage to one of the cooling fins), so a pulley replacement should see you good for the next 80-100k miles.

Cheers,

Mike
 
Thanks Mike, great advice.

I'll keep an ear open for the moment, and if it gets worse I'll just bite the bullet and get the pulley changed.
 
If you've not already done so, if/when you get the pulley done, change the belt too - well worth it.

Cheers,

Mike
 
Now had a look under the bonnet, not of course that there is anything obvious to see. Is the large metal object with the coiled spring in it (next to the alternator) the belt tensioner? If so it seems to be vibrating quite a bit, and I wonder if it is the source of my mysterious noise.
 
It is indeed, but why is it vibrating? Is there a fault with the tensioner itself (possibly a bearing failure) or is it just vibrating due to something else in the system being bad (namely the alternator pulley)?

The only way of telling really is to release the tensioner, lock it in place and examine each part in turn.

Cheers

Mike
 
I recall that thread Phil. I don't think mine looks that bad (yet) and the noise is only at idle (yet) but I'll book it in next week and have the pulley and belt changed just to be on the safe side.

Thanks
 
Only noticed mine on idle as though the belt was slipping then i started to here a rumble like the bearings in the alternator where going, but none of the above pop the pulley came off just good job it happen as i pulled up at home and not on the motorway

Phil
 
Hmm, this sounds worrying like the same symptoms. Perhaps I'll not use the car much until I get it looked at. Thanks for the advice.

John
 
Just phoned my ever helpful local VW dealers (Barnetts of St Andrews) who have agreed to check it out for me this afternoon.
 
Car has been diagnosed as needing a new pulley, a new tensioner and of course a belt. Parts are on overnight order, and I should get it back by lunchtime tomorrow, wallet suitably lightened.

Very glad I've got a good ear for a noise, and that there is such good advice readily available here, as together they probably saved me a roadside emergency.

Thanks again chaps!

JH
 
No worries John - for reference, the pulley is around £55, the tensioner around £67 and the belt about £15, so add on labour to be ready for the bill!!

Cheers

Mike
 
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