I've have the fabia vRS for a year now and in that time I've had 2 tensioners go on it. One genuinely had collapsed and the 2nd has thrown two belts to the side causing them to fray or so we think. We (Me and my dad) are now wondering if maybe the Alternator pulley could be at fault causing the belt to be pushed off the tensioner. 

 

Anyone got any clue's or experience with this? 

Coincidently I had the same issue on a VW Passat (1.9tdi - '98)

Edited 4 May, 201412 yr by Gazedd

We (Me and my dad) are now wondering if maybe the Alternator pulley could be at fault 

 

Absolutely. The alternator has a free wheeling pulley and it can seize, causing the sort of issues you have been experiencing. That's the next thing I'd check.  

Recently happened on mine belt come off stupidly thought nothing of it then come off again the pulley had actually come off the alternator no warnings either at a closer inspection tiger were little metal filings that were obviously from the alternator pulley

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the alt pulley is free spinning when done by hand however our thoughts are that it could have miss-aligned - is this possible?

Yes, I think the bearing can also wear causing out and in movement of the pulley, and associated movement/wear of the belt. 

Tiger would definitely cause a stir.

Would first check/replace the alternator pulley.

On my old car the pulley seemed OK but when I fitted the new one you could tell the old one was not right. The old one killed the tensioner.

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On my old car the pulley seemed OK but when I fitted the new one you could tell the old one was not right. The old one killed the tensioner.

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What was the difference? Was the pulley moving in any way at all? Any advice would be greatly appreciated since you may have had the same issues.

What was the difference? Was the pulley moving in any way at all? Any advice would be greatly appreciated since you may have had the same issues.

Once I fitted the new pulley I realised how much easier it worked than the old one. With the alternator on the bench, if you spun it then grabbed the pulley the new one was smooth, the old one sort of grated.

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I've recently changed my alternator, belt, tensioner and pulley as I had metal filings on it and it was making a chattering sound, since changing it I have had no problems with starting my car.

So just to bring this post up to speed for anyone who may search on this in the future:

Today we changed the alternator pulled and it wasn't good at all. The new one runs much much better!

Excellent. Glad you got to the bottom of it.

Now just to replace the tensioner again as it's buckled and hope that the alignment doesn't kink again!