Gearbox/turbo whine?

[jewski1984]

Morning all



My Audi A4 Dynamik has started to make a whining noise, when I say started, I probably noticed it about 6 month ago... It happens both in neutral/stationary and when driving. The pitch of the whine also changes with the gears, when I change up a gear the sound becomes harder to hear until around 1500 rpm or so when the revs start to rise again. More noticeable at low speeds due to less road noise etc. I've uploaded a video for your audible pleasure on vimeo:



I should add it was in for a service a couple weeks ago the mechanic never picked up on it, I asked him to check gearbox oil level and he said it was fine.

Any advice is greatly appreciated!!

 

[jewski1984]

Bump, anyone?

 

[cashutt]

If it’s changing with the revs it could be something driven by the timing belt. Like the A/C compressor, alternator, water pump or just a pulley bearing. Unless you mentioned it specifically to the mechanic he may not have picked it up. Try turning on/off the a/c to see if the noise changes, turn all the electrical stuff on to see if that changes it. Reach down and see if any of the pullies have any wiggle in them. Don’t think it’s the turbo as that makes a more owl-ish noise.

 

[spartacus68]

Does sound like it's connected to the timing belt and potentially a bad bearing. When was it last changed? I'd go easy until you can have this checked out.

 

[jewski1984]

If it’s changing with the revs it could be something driven by the timing belt. Like the A/C compressor, alternator, water pump or just a pulley bearing. Unless you mentioned it specifically to the mechanic he may not have picked it up. Try turning on/off the a/c to see if the noise changes, turn all the electrical stuff on to see if that changes it. Reach down and see if any of the pullies have any wiggle in them. Don’t think it’s the turbo as that makes a more owl-ish noise.

Thanks for the reply. I took off the serpentine belt and ran it to rule out alternator etc. It still made the noise with the belt off. So that leaves me thinking it must be either the turbo or input shaft bearing maybe for the gearbox? I'm not sure of the best way to diagnose this now. The fact it whines in both neutral and in gear doesn't help!

 

[jewski1984]

Does sound like it's connected to the timing belt and potentially a bad bearing. When was it last changed? I'd go easy until you can have this checked out.

Had the belt off and ran it, the noise was still there. So that makes me think again that it's maybe the turbo or input shaft bearing on the gearbox. Not sure how to proceed though and check this

 

[spartacus68]

Had the belt off and ran it, the noise was still there. So that makes me think again that it's maybe the turbo or input shaft bearing on the gearbox. Not sure how to proceed though and check this

No idea - probably a Audi specialist (and I'm not talking main dealer). I can do most jobs, but haven't done a timing belt. You really need to get the car in service position with the front off and check the pulley bearings. A VAG specialist will probably recognise the sound,. Anyway - keep us posted.