Any Thoughts On Where Noise Is Coming From
 

I've had an unusual whining noise from my car, but only under normal acceleration. Depending on the road noise, it can be heard from speeds of 30 to 70mph (it sounds like it's coming from the transmission tunnel which is why I put it here). It's been there ever since I bought the car four years ago and finally decided to try and capture the sound.

I've uploaded a video clip to YouTube, if you want to listen to it. The link is as follows:

https://youtu.be/f1dh6RcGf5Y

You can hear it best around the 20-30 second mark, and see when I'm accelerating.

I don't know if this has anything to do with it, but I just discovered that one of my intake manifold actuators isn't working properly. Looking from the front of the car, it's the one on the left. I just happened to see another video on YouTube of how these work, and since I was using my GoPro today, I thought I'd capture these as well. They both deflate when the ignition is turned on, but only the right one inflates when you rev the engine. Both inflate again when engine stopped.

I would be pretty sure that the noise is not related to the manifold actuation. It doesnt sound too good though, I am afraid to say. Did you not get the tx serviced at one stage at Mackies? If it has been there since you've had the car then it (surely?) would have been picked up there? But it certainly sounds drive train related.

It sounds to me something more like a washer or shield or metal fixing rattling, maybe just something on the undertray?
If it was inside the transmission, with all the lubricants/fluids, that type of noise seems implausible.

Have you checked for loose heat shields. I had one once (on a Beemer) that was bolted up tight, but the shield had broken right around the bolt head. Result, it looked OK, but at speed would free up and make a racket

+1 my thinking also

Could it be related to the air conditioning? I know mine makes a little noise, not like that though. :Confused:

Yep, got it serviced with them in October 2014. They did say there was signs of wear, but didn't elaborate. At that time, there would have been about 67,500 mile on the clock.

HPsauce/tonupkid - Just wondering if you're listening to the wrong noise. There is a noise at the very start and around the 10 second mark (like crackling from a LP). Ignore that, as that was from the GoPro resting on my left foot. I get what you mean by something loose causing it, but it doesn't alter with speed (which I would have expected). The only change in tone is when you take your foot off the accelerator and the noise stops. I was doing about 30mph when I did that video, but it would sound the exact same at 60mph.

Wasn't sure if the GoPro would pick up the sound at all, so closed the windows and sunroof, and turned off all the A/C and fans.

I've done the usual Google search of whining related noises from engines and transmission (both Audi and generally), but nothing I find seems to relate to my problem.

It could be a bit of noise from the exhaust? I had a similar noise under load when I first rebuilt the engine. Turned out it was the manifold-exhaust pipe joint on the driver side joint 'bedding in'.
It was such an awkward pig to get at I finally got a couple of turns at the nuts after 3-4 months and it seemed to cure the problem

Given that its throttle-related and not speed-related I would say it's forward of the flywheel and not something rotating. The way it behaves with the accelerator pedal says vacuum / intake leak to me.

The manifold pods might actually be a clue - if one of them has a split diaphragm it could be making a noise as its leaking. Possibly it could be a leak in part of the SAI valve system which reduces the vacuum such that only one pod can activate. Possibly something around the throttle body boot / oil separator.

I would first try disconnecting the vac pod solenoid valve, just to rule those out. It will throw a code but thats easily cleared. If that doesn't affect it, have a good look around the back of the engine with a torch looking for split hoses.

Pretty sure I got the right one, when you put your foot down it's there. Suggested to me that very slight movement of engine/drive/whatever under load was releasing something metallic and dry. Constant noise as you said so not rotating, hence my suggestion.

And aren't manifold flaps mainly rev-related, though obviously the vacuum driving it is somewhat throttle-related. You could check that by manually overriding gears.