2.0Tdi Strange noise when lifting off throttle

[iwcham1979]

Hi guys. Greetings from Serbia. My ALtea 2.0Tdi has developed a strange noise, noticable when i lift my foot off throttle at lower revs. It is noticable when i shift say from 2nd to 3rd gear, or when I press the throttle harder and let go. The moment I let go, I hear the rubbing sound, How shall I picture it for you...?! Try rubbing your palms up and down just once. It's very much like it, even the split second pause in between. I can avoid it if I accelerate gentlier. Is this serious? There is no smoke, no loss of power. It can't be heard with the radio on.... The car is manufactured in 2007, and has only 36000km. I'm the first owner so mileage is true.

 

[iwcham1979]

bump

 

[tony19b]

I get this sound on my Toledo 2.0TDI, mine's a DSG so I hear it on light throttle upshifts, a sort of gasp. I also have the police siren noise. Having said that, the car has never run better!

 

[iwcham1979]

Ok. Tnx for your answer Tony. Strange though...the noise wasnt present before, yet no warning lights, nothing...

 

[drummer.gavin]

Is there a DPF on your cars? I get an odd rubbing/grinding noise when the DPF is clearing itself.

 

[iwcham1979]

I dont know about pdf. I tried revving with the hood open in the garage. Upon revving to 3000rpm and lifting off throttle, there is an ugly noise of air escaping somewhere in small amounts at about 1000rpm, like ps.ps..ps..ps..ps. Is this normal. Maybe the sudden pressure build up in the turbo, thus the occurence of this is normal?!

 

[iwcham1979]

I've listened for that rubbing noise. It seems to be less likely related to engine, since it's not present when revving in neutral. I can hear it even at low speed and as low as 1800rpm. It definitely needs a kind of jolt to be provoked, so i'm guessing it is brake calipers or similar non engine related... Im now only concerned with that pssss.psss several times quickly when suddenly revving to 3500rpm and letting off throttle. It is not heard while driving, only with the hood open and in neutral. It has probably been present before, but i now related it to the rubbing noise problem by accident. Is that normal!? Maybe turbo releasing sudden pressure build up, or similar? I am now more woried about it, even though i stumbled upon it by accident and while trying to pinpoint rubbing issue... I would be greatly thankful if anubody could try this. Agressively on throttle from idle to 3500-4000rpm with the hood open, and release. On its way down to lower revs, at about 1000rpm you should hear pss..pss...psss. Thanks guys for help

 

[iwcham1979]

So, since i've "solved" my problem, it's in order to share it with you, because many of you have met with it, or will in the near future...
I have been to the dealer's today. They said the noise was normal, and showed me a print out from Audi confirming that, and specifically instructing the service not to conduct any repairs as the condition is normal. It's the noise from the turbo, as it gets the highest pressure at 2000rpm, so lifting off throttle or shifting gears causes the release of pressure in the opposite direction. I told them that i hadn't heard the noise before. Their response was that there probably happened a subtle change in the angle of the blades within the turbo, resulting in the occurence of the rubbing/abrasive sound. However, they assured me that the turbo is fine, and as healthy as it can be! What do you think?
Cheers!

 

[mart4875]

My 2.0 TDI has recently developed the same noise. Like yours it only happens in the lower gears and more noticable when cold. Almost like a turbo flutter. Glad it isnt anything to worry about.

 

[iwcham1979]

Yep, definitely nothing to worry about. As I was told, only a microscopic change in the angle of the blades within the turbo. It will probably disappear and reappear over time Many cars are new like that.