Hi all,
Hope that someone can help me understand something....
About 5000 miles ago (8000 km) I've changed my timing belt. The operation was performed by the book, changing all in the timing belt path (belt, tensioner, roller, water pump, etc). Timing belt is Contitech, roler and tensioner are INA.
Now, after this mileage, a while after the engine is started (at cold start all is OK) there is a cyclical whooshing noise from the upper timing belt area. As something is lightly rubbing on something.
How can I tell that's the timing belt ?
Because the timing belt has on it some white markings (type, producer, serial no., etc) and through a small gap in the timing cover I can see the belt and see those markings. The cyclical nature of the sound can be synchronized in a way with the appearance of those markings. They have the same period/frequency.
But nothing is rubbing and the timing belt seems to track nice and OK on the upper timing sprocket.
More of that, I've conducted a small experiment and when the engine was running, I've lightly spray some clean water over the timing belt through that gap in the timing cover and the sound stopped almost immediately after the spray. But reappeared later, progressively, after the water has evaporated.
What can it be?
Did you saw/heard things like this?
Thank you!
Alex

My cam belt sounded like that before i change mine it was rubbing due to a failed tensioner bearing. perhaps your kit had a faulty tensioner.
Yours could be caused by either:
1) Tight cam belt ; Noise goes when warm ( Cam belt tensioner too tight, Noise goes when belt warms up. (replace faulty belt tensioner)

2) Dry Cam Sprocket Bearing noise disappears if lubricated.


Here's the sort of noise a faulty tensioner will make.

I think isn't a problem: the markings on the new belt sometimes cause some noises...your test with water it's a good idea and confirm that the problem is some kind of "dirt" on the back of the belt ( the markings).

once the "ink" of the markings will be slighty worn, the noise will stop also with engine in temperature

turboextreme, the noise appears when the engine is warm/hot... there is no noise on a cold engine, so the exact opposite...
the bearing problems tend to minimize when getting hot and the fact that the sound is being synchronous with the belt rotation - meaning the sound will appear on a certain position of the belt on the timing ensemble - leads me to believe is a belt issue, not a bearing issue.

I'm guessing here, but I think a faulty belt that has teeth spacing or profile cut wrongly in the area of the white markings. How can you tell if its the Timing belt, put another one on

Is it a manual or automatic timing belt adjuster on the FL2? I've always found that timing belts get tighter when hot and if too tight, can make a synchronious squeak/creak on tickover. Past: FL2 TD4 HSE Auto
Evoque SD4 Dynamic Lux Auto
Present: Audi A3 S Line.

It's spring tensioned automatic.

Ah well, there goes my theory! Sorry. Past: FL2 TD4 HSE Auto
Evoque SD4 Dynamic Lux Auto
Present: Audi A3 S Line.

It seems that the problem was due to the dust...
Lately I drove through some dusty roads and some of this dust have found its way to the timing belt.
The belt, during functioning, becomes slightly charged with static electricity - due to rubbing against various sprockets, idler, tensioner, etc. - and those particles have adhered to its surface.
A good and thorough blow of compressed air and the strange cyclic whooshing sound has gone away.

Steve D wrote:

Ah well, there goes my theory! Sorry.

Oh well, your theory was as good as my guess, we were both wrong

alex_pescaru wrote:

turboextreme, the noise appears when the engine is warm/hot... there is no noise on a cold engine, so the exact opposite...
the bearing problems tend to minimize when getting hot and the fact that the sound is being synchronous with the belt rotation - meaning the sound will appear on a certain position of the belt on the timing ensemble - leads me to believe is a belt issue, not a bearing issue.

My belt was changed 2 days ago by a garage and now I have noticed exactly this. I will run it this weekend for a few miles and if it persists it will have to go back.

The new belt though should not be dusty  FL2 MY10 TD4 GS traded in at 2 years
FL2 MY13 TD4 GS Current

Mine stopped doing it after a year...

Initially thought that is because of dust, but no. After each air blow, it stopped for about 1-2 days, then appear again.
During some experiments, I sprayed some water on it and again silence for 1-2 days.
In fact, when air blowing it, water vapors from compressed air stream probably had the same effect.
Maybe when dry, the belt material was "too" dry and squeaky and made that sound when rubbing some sprockets.

Probably it was a little too tight and now it's inside parameters.

If Alex is stumped were all doomed I tells yer

A good result  2008 xs
Snorkel
raised axle/gearbox breathers
Mantec tank guard
Cb radio
Blanked EGR
Sump guard
Scratches
Snolkle