"Clacking" noise on engine start up

[Jonny5isalive]

Originally Posted by D5meister

We all see different things on these vids as we all have different computer, tablets, media phones.


What I see is the tensioner pulley wobbling. If true this is about to let go.

The acid test is to fit a torx wrench to the tesioner housing with a long arm - hold off the tension and the belt and manually sample for play, if it moves like it appears (to my eye) in the vid your on borrowed time.

hope it is ok and its a trick of the light.

Thanks, I WILL try this tomorrow as she's tucked up for the night now.

Am I right in thinking it's a T60 Torx to hold off the tensioner?

The pulleys have all been checked and it's only the belt that moves a few mm's across the tensioner, not the actual tensioner pulley itself - (even if it appears so). The alternator I've had fitted recently was from an XC90 but same part number as old one. Maybe there is a slight mismatch on the pulley of the new alt? Just clutching at straws here.

For the cost of the parts (about £70 on eBay), I'd do it myself but I'm still very much just learning and not confident enough yet. For all I know, I could have someone change all the parts or do it myself and still have a bit of a wandering belt... Doesn't stop the car going like an armchair rocket.

[Brendan W]

It is hard to tell from the clip but I can't see any movement of the tensioner pulley. It does look as if the alternator pulley is in the wrong position and is feeding the tensioner at a slight angle.
I mean the other way around, the tensioner feeds the alternator. If they are slightly misaligned the belt will try to straighten but have farther to go and because the tensioner is spring loaded you get a yoyo effect going on. If pulleys were swapped with the alternator maybe it wasn't seated fully.
Another possibility is that the pivot for the tensioner arm is worn. This would be fairly difficult to spot as the spring on the diesel tensioner is very strong.
The tensioner looks very old. Afaik the old high hat plastic end cap in the tensioner pully is gone almost ten years.

[Jonny5isalive]

Originally Posted by Jonny5isalive

Thanks, I WILL try this tomorrow as she's tucked up for the night now.

Am I right in thinking it's a T60 Torx to hold off the tensioner?

The pulleys have all been checked and it's only the belt that moves a few mm's across the tensioner, not the actual tensioner pulley itself - (even if it appears so). The alternator I've had fitted recently was from an XC90 but same part number as old one. Maybe there is a slight mismatch on the pulley of the new alt? Just clutching at straws here.

For the cost of the parts (about £70 on eBay), I'd do it myself but I'm still very much just learning and not confident enough yet. For all I know, I could have someone change all the parts or do it myself and still have a bit of a wandering belt... Doesn't stop the car going like an armchair rocket.

I haven't tried what I said I was going to, but i HAVE bought an genuine Aux belt kit (belt and tensioner) and going to do it myself in the near future, with the help of Youtube videos. If the belt still wanders afterwards, then I'll change the pulley on the alt. May as well jump in the deep end...

[Jonny5isalive]

Originally Posted by Brendan W

It is hard to tell from the clip but I can't see any movement of the tensioner pulley. It does look as if the alternator pulley is in the wrong position and is feeding the tensioner at a slight angle.
I mean the other way around, the tensioner feeds the alternator. If they are slightly misaligned the belt will try to straighten but have farther to go and because the tensioner is spring loaded you get a yoyo effect going on. If pulleys were swapped with the alternator maybe it wasn't seated fully.
Another possibility is that the pivot for the tensioner arm is worn. This would be fairly difficult to spot as the spring on the diesel tensioner is very strong.
The tensioner looks very old. Afaik the old high hat plastic end cap in the tensioner pully is gone almost ten years.

The replacement alternator came with it's own pulley, my old alt was removed as one piece and swapped. Could the new alt pulley be the problem? Can my old alt pulley be swapped over or should I just buy a new one and fit that?

I have no record or receipts in the full history that indicate the belt and/or pulleys ever being replaced, so yes, they will be the original parts I reckon.

[Jonny5isalive]

[QUOTE=Brendan W;1956430]It is hard to tell from the clip but I can't see any movement of the tensioner pulley. It does look as if the alternator pulley is in the wrong position and is feeding the tensioner at a slight angle.

I've had an idea. What if I was to disconnect the old alternator and unbolt it to check its mounting threads and surface? As you said, it doesn't look to be in line correctly. How easy is this to do? I've got plenty of tools.