vibrating noise & belt slip on full lock- serpentine belt tensioner?

[VtecJunkie]

Hig guys,

Been having a problem with ma 2002 audi a3 1.9 tdi 130bhp sport. There is a distinct vibrating sound, almost knocking sound coming from the cambelt, most noticeable on idle and when cold. Seems to dissapear to some extent when warm but still occasionally there.

Another symptom was on full lock the belt sounded like it was slipping, screeching- but only on full lock.

Another symptom was, If the car was idling the vibrating sound could be heard.. but if you turned the headlights on strangeley it would dissapear. This led me to beleive it must have something to do with the alternator belt.

I had a look at the serpentine belt pulley/tensioner and it was moving from side to side- is this normal? It was this making the sound.. as if I held it still with my hand when idling the noise would disspear completely.

Do i need to replace this? I also noticed the belt was slightly cracked which would make sense.

Isn't replacing this and the serpentine tnesioner/pulley part of the cambelt job though? or not? I ask as Audi only replaced the cambelt 4000 miles ago...

Lastly, how hard is it to replace the tensioner for the serpentine belt?

[V6sline]

Hi VtecJunkie i have exactlt the same problem on my 2.5tdi a4 did anyone get back to you???

i had exactly the same question...

[VtecJunkie]

Yes- have a look at your serpentine belt tensioner that will be where the noise is coming from. The root cause though, is likely to be a seized alternator pulley, which is a cheap and easy fix.

have a look here and on the links posted in this thread; https://www.vwaudiforum.co.uk/forum/s...ad.php?t=81370

[V6sline]

Thanks, i hide a sneeking suspicion it could be something to do with the alternator, took it to a couple of garages and they replaced belts and stuff, one even said power steering rack could be on its way out I will get someone to replace pulley! cheers!