Thread: 300 TDI serpentine and accessories belt wear

I seem to be having trouble getting the second and third video to work. Anybody else had this problem?

edit: I changed them to unlisted not private in Youtube

Check the PS and water pump pulleys by pulling in and out on them, my PS pump pulley started walking out shredding the belt.

I'm getting something very similar to your first vid.
That squeaky tick noise at idle.. cold or hot(for me tho).
At first I thought an issue with the new waterpump I recently fitted.
It started just after I fitted waterpump, alternator and refitted and locktited the harmonic balancer.

I remove the serpentine belt and tick goes away.
I take off the fan (belt back on) and noise comes back.. so for sure it's waterpump, PS pump, Alt pulley or adjuster .. all basically brand new, along with the serpentine belt.
Now with fan off, I can place hand close by and add/remove pressure off the belt tensioner. Both more and less pressure on the tensioner and the squeaky, metal sounding tick noise disappears.
Tensioner is barely 1 month old .. but ATM I'm leanign towards a slightly faulty one .. maybe.

I'm going to refit my old one tomorrow and see if that gets rid of the noise.

The only other variable and worrying one for me tho is the main idler fan hub bearing. On mine I have about 1mm of side to side play .. thinking that this may be the culprit.
I'd rather not have to deal with that mongrel of a bearing that's technically not replaceable .. but AULRO sources have described as doable.
The only reason I'm placing the fan bearing as last on the list is the difference in noise when I add remove tension at the tensioner.
if the bearing was making noises you'd expect an increase in noise with one or the other amount of loading of the tensioner.
At one point I had removed so much loading off the tensioner, I could see the belt slipping slightly .. didn't want it to jump off so didn't push my luck in that sense .. but me thinks start with he easy stuff (tensioner) first.

Something to look into on your main serpentine belt, but it has a strange wearing mark almost down the middle of it relative to it's running direction.
That is, front half is dull and matte in appearance, and the back half is shiny and glossier by comparison.
This would indicate a possible something rubbing and marking the belt as it weaves it way around.
The only two items that contact the smooth face of the belt are the PS pump pulley and the tensioner. Could they have worn bearings and be running slightly askew.

Another thing I notice with yours relative to mine, is how much less bounce your tensioner has compared to mine.
I reckon I'll have to look into why my tensioner(both old and new) bounces up and down 10 times as much as your does at idle.
Once I have some revs on the engine(fast idle .. maybe 1K RPM) it does smooth itself out tho.

Just an update at my end to barnbiscuit's tappy noise:

I just flushed the coolant(had some flushy stuff in it yesterday), and when I started it to bleed it and test for leaks, my ticky noise got worse and louder.
Totally forgot about wanting to refit my old tensioner(which has a 0.5mm play in the idler bearing part).
New tensioner has a nice tight bearing in terms of side play, but I replaced it with the old one(complete) anyhow.
Sorted the ticky noise immediately

Thanks for your responses LoneRangie and Arthur.

1.So took the serpentie off. Car was luke warm but still heard the ticking noise especially prominent when the engine was reved.
-No Play in the pulley's for the PS, Water pump. Some movement from the tensioner pulley but couldn't find any other cause of uneven belt wear.

2.Then took the accesories off and no ticking noise at all. Sound was completely gone even when revved.

Will turn it over in the morning when its stone cold to be sure.

Assuming its not injector tick or some part of the serpentine assembly what is there on the accesory assembly that could cause this?
No play or movement in the AC pulley. A little movement on the accesories pulley but the tick seems to be coming from the left side of engine and higher up. It doesn't seem to be coming from accesories territory at all.....

accessory belt only runs around AC compressor and two idler pulleys, one of which is obviously the manual tensioner.

With that belt removed, do the two idlers run freely, have any play, or any such indication that bearings may be worn.
Do all three accessory belt tensioner bolts tighten up nicely. Don't over over tighten them, as they are easy to strip(aluminium housing!) .. oh! and don't ask me how I know this
That would be where I'd be concentrating my efforts.
You can very well run the car without accessories, but of course that means no AC!

I guess something else that could tick, in metallic sounding fashion could be the idler pulley covers.
Use a screw driver to prise the flat covers off the pulleys to reveal each nut(or bolt)

I recently replaced my accessories bearings but the whole bearing and idler pulley, rather than source bearings.
They have a retainer circlip to hold the pulley onto the bearing and one of them the circlip was a bit thicker than it should have been, so as I tightened up it's nut, it pressed hard on the circlip which pressured the bearing and made it bind.
Had to find an appropriate sized washer not too thick, and the right ID and OD for the washer to sit right on the bearing inner race.
But as the washer may have not been seated perfectly centred, it must have just been tapping on the circlip. It ticked(much more quietly tho) for a minute or two, and obviously wore itself(or centred properly) to a point where it didn't tick any more(and no binding).

Other things it could be:
a small thing just rubbing at certain spots on the inside of the compressor pulley.
Remove the three bolts holding the accessory belt tensioner and check their lengths. Make sure they're not overly long and possibly hitting the IP cambelt pulley.
My(now gone) tick drove me mental, and then more so as it turns out it was the least likely thing I was expecting .. a NEW part gone wrong!

But that noise you have in Vid #1, is exactly as mine was at idle, gone at only a faster idle(say 900RPM) and back at idle. Now gone with the new tensioner.

Originally Posted by AK83

Don't over over tighten them, as they are easy to strip(aluminium housing!) .

Any idea of the Torq Specs? I'm waiting on my Haynes manual to arrive.

Originally Posted by BarnBiscuit

Any idea of the Torq Specs? I'm waiting on my Haynes manual to arrive.

Tensioner has a 1/2 drive access for a torque wrench.

Rave says:
Tensioner tension(for belt) = 35Nm
The 3 retaining bolts = 25Nm