Odimel

I am having a "noise" issue with my 2016 A6 3.0T. I first started hearing this weird pumping noise coming from the engine bay.
Heard from the cabin, its really loud and distinct, there's no way Audi designed the car with this much noise.
I wanted to know, is this normal?? Any one else hear this?

Attached is a short clip. Listen for the lowest frequency thudding sound, I have to move the phone around to really hear distinctly.
In person its really loud and overtakes any normal engine sound and all you notice is the low freq thudding. Alost sounds like my old car misfiring.

https://c.mail.com/@7225784131848845...RYa2bWZtJ0Y43g

This noise is not heard at startup. Only notice it after a few miles drive and after its well warmed up.
Its very loud and distinct in park/ neutral. When in drive it is more muted (still hear it when at lights). No dash warning or lights of any sort. Changes with rpm change.
Took it to the dealer explained it to them, the rep listened and said they will check it out. And came back and said nothing was wrong.
I'm pretty sure after the oil change they turned it on and didn't hear anything, as expected.

Let me know if anyone else wants more info.

gk1

Purely a guess, but it sounds like maybe Secondary Air pump. But if that is faulty it should throw a code.

xanmato

I have that EXACT same sound. Car must be warm, and must be driven for a few miles. I am betting once you stick in it Drive or Reverse the sound goes away or extremely diminished. Putting it in park or neutral and the sound comes back. I am guessing it's the torque converter/flex plate. It could be a cracked or warped flex plate, just enough to rub when it gets hot enough for the metal to expand the tiniest amount.

The good news is that since it seems to only occur in neutral or park after a drive, it doesn't seem to be detrimental, at least very quickly, as we usually shut the car off after a drive. The converter/plate seems to cool very quickly as I have tested down to about a few minutes of engine off and the noise will not occur after re-starting unless driven again to get hot. So the window of noise/possible damage is actually quite small. I have had this issue for about 25k miles now with no changes.

The bad news is that I don't know the exact cause since I don't want to pull the trans out to get a look in there. So hopefully you are not a one post ghost and can get the dealer to tear it down and report the findings. It would be easy enough to get it on a lift and listen to the trans housing to pinpoint the location without ripping stuff apart.

Odimel

Yes you described it perfectly. Last time I took it in for 35k service so I'm sure any noise complaint wasn't their top priority. They were a couple days behind on servicing many cars, so they were trying to get things out quickly.
I will make another appointment with them specifically for this and ask someone to come for a quick drive. It should be covered under warranty.. At the very least I want to see what they find.
What makes you think its the torque converter?

I will take it in for sometime later this weekend or next week. I'm pretty busy right now so it may take a while. I will update this thread when I know more.

xanmato

If you get under the car near the transmission you should notice that it is a lot louder. At first I thought it would be rod knock, but rod knock is almost always double rpm speed. Once I noticed the sound disappeared when putting it in drive or reverse, I knew it was most likely the flexplate slapping against the torque converter. A cracked flexplate with heat can warp just enough for once of the bolts to start clipping the torque converter. Now the sound goes away or is completely diminished when in drive/reverse since the torque converter starts spinning, matching the speed of the flexplate.

Saabya6

IF you can, have your indy or dealer check your transmission coolant solenoid/pump, which is located by the drivers front wheel, between the jackpoint and wheelwell. I had similar sounds after having mine replaced, and still haven't tracked down the issue.

Odimel

Car has been at the dealer since July 2nd.. 3 different techs spent a week trying to replicate it and finally did. But they can't determine where its coming from. So someone from Audi (expert or whatever) is coming over next week to help isolate the issue..

xanmato

They would have to drop the transmission and or engine to inspect the flexplate/torque converter, probably why they can't determine where it's coming from. I would be surprised if something else was the issue. Thanks for the update though and keep us posted.

Odimel

Just got the car back. Tech looked at it and said it sounds normal. Sound apparently is coming from the supercharger trying to cool itself down.
I don't know if I believe that, and I've got nothing else to say to them.. They had the car way too long and drove it many miles!
Only thing to do is compare it to others with the 3.0's.
How confident are you in the torque converter making that noise?

gk1

Tell them to prove it by pulling another 3.0T around that sounds the same. They must have a used one on the lot somewhere.