Thread: WTF is this noise on my 300Tdi!!!?? (video clip)

Its a temp fix but some have reported that even a new tensioner hasnt solved it.

From my own experience, I'd bin the old tensioner, but keep the pulley with the new bearing as a reserve on the shelf. The tensioner - if the plastic bearing in the middle of the two halves has worn out from all the movement, it will always make a noise in the future, just aluminium to aluminium contact - the squeal is from the bouncing around. If its worn out so much as to need more than a 5 cent piece to stop movement, you run the risk of the belt running right off the pulleys, especially if it gets wet, I've seen this happen unfortunately to my own vehicle whereby it shredded a new belt, cutting up the ac belt at the same time. The 5 cent piece helps to correct the angle for a while helping the belts say quiet, but eventually the plastic bearing will wear out. I bought belt after belt, cleaned the pulleys and still the noise. Just get the new tensioner and a new belt at the same time - a new tensioner alone with the old belt might inherit the old noise.