2016 S6 weird acceleration noise/rattle

[OF Hero]

I noticed it the first time a few days ago when driving with the windows down around a high-walled center divide so I could clearly hear the sound echoing from underneath the vehicle...almost like a "pebbles in a tin can" kind of sound/rattle/crunch when giving it low throttle that lasted a couple of seconds. No gear changes involved. I was driving past a construction site at the time so I thought it was maybe their equipment but I heard it again later, then disappeared for a few days until I heard it again. Car only has 500 miles and drives perfect. Do the sport exhausts have valves that can make this noise?

[gk1]

Was it switching from 4 cyl to 8 cyl mode at the time? That should be your only chance to hear exhaust valves if you can hear them at all.

[OF Hero]

Was it switching from 4 cyl to 8 cyl mode at the time? That should be your only chance to hear exhaust valves if you can hear them at all.

Well while it was at a relatively low speed, it was with throttle so I doubt it would drop to 4 cyl at that time, right?

[gk1]

Well while it was at a relatively low speed, it was with throttle so I doubt it would drop to 4 cyl at that time, right?

Watch fuel consumption bar...if green it is 4cyl mode, otherwise 8.
FWIW you can be giving throttle and stay in 4cyl mode. Just has to be very light.

[OF Hero]

Watch fuel consumption bar...if green it is 4cyl mode, otherwise 8.
FWIW you can be giving throttle and stay in 4cyl mode. Just has to be very light.

So I've found I can replicate it by allowing it to go into green (4 cylinder) and then when I give it throttle it goes back to 8 cylinder and the noise is briefly heard. Sounds almost like the direct injection clicking at idle but more rapid and slightly more harsh. Is this just the extra 4 cylinders being reactivated?

Surprised nobody else has commented on this in reviews, etc. Or do I just have super human hearing? LOL

[gk1]

So I've found I can replicate it by allowing it to go into green (4 cylinder) and then when I give it throttle it goes back to 8 cylinder and the noise is briefly heard. Sounds almost like the direct injection clicking at idle but more rapid and slightly more harsh. Is this just the extra 4 cylinders being reactivated?

Surprised nobody else has commented on this in reviews, etc. Or do I just have super human hearing? LOL

I've personally not heard that noise so maybe it is that you have excellent hearing. I can occasionally FEEL it switch back to 8cyl mode in certain circumstance but I do not hear anything.

[OF Hero]

Just wanted to update this so I could get more opinions.

The noise progressed to the point where I could easily replicate it anytime I gave it some gentle initial throttle over 35 mph. Took one of the Audi service guys with me for a drive and he heard it too. Said he thought it might be some heat shield underneath making a metallic rattle. They took it for a look the next day and said they couldn't replicate the noise. The put the car on a lift and inspected underneath and said everything seemed tight and gave me the car back.

It has worsened over the past week where the noise is VERY easily replicated - almost always happens when I let off the gas a bit, then ease back on the throttle and it makes this metallic clicky/rattle noise that sometimes is only 1-2 seconds, other times can go on for nearly 10 seconds. It is quite harsh and not "normal" sounding. I very strongly feel it's coming from the right side, underneath the vehicle. I don't think it has anything to do with the 4-8 cylinder switch as I had previously thought since it happens regardless of that mode. Exhaust? Drivetrain? The car only has 1200 miles and drives fine, but I have real bad OCD and regardless, this kind of noise from an $80k car is really annoying (unless I am totally oblivious to some normal function that's going on). Should I request a second look?

Of note, I have also noticed that when in park, the passenger side exhaust makes no idle rumble. Plenty of rumble and noise from the driver side, but the passenger side is virtually silent. Is this by design?

Please help!

[RAF_S7]

I think you should take a trip back to the dealer and book it in for some investigatory work under warranty.

The noises you describe do not seem to be normal. My S7 (same drivetrain) does not exhibit any of these symptoms.

BTW the 2016 models have a valve on only one side - your drivers side.

[OF Hero]

Yeah I'm taking it back today for a 2nd look, the shop foreman is around today so he will ride with me.

The exhaust valve only on the driver's side, does that apply to the sport exhaust too?

[Djpeaksd]

I think you should take a trip back to the dealer and book it in for some investigatory work under warranty.

The noises you describe do not seem to be normal. My S7 (same drivetrain) does not exhibit any of these symptoms.

BTW the 2016 models have a valve on only one side - your drivers side.

JK isn't there also a valve on the passenger side on the muffler?

[RAF_S7]

JK isn't there also a valve on the passenger side on the muffler?

On the 2016 model S6/7 Audi deleted the 2 valve left/right setup and replaced with a single valve on the input pipe to the passenger side rear muffler box. (Your driver side)

I don't know if the sports exhaust or the RS has two valves. Sports exhaust is not an option for s6/7 here in UK

[Djpeaksd]

On the 2016 model S6/7 Audi deleted the 2 valve left/right setup and replaced with a single valve on the input pipe to the passenger side rear muffler box. (Your driver side)

I don't know if the sports exhaust or the RS has two valves. Sports exhaust is not an option for s6/7 here in UK

Ah ok! Cause I have sport exhaust and have two valves so that explains it!!!

Sent from my SM-G925T using Tapatalk

[jagata]

My 2013 S6 makes a similar noise also with light acceleration that last 2 seconds but mine can be heard inside the cabin. I have a AWE exhaust and the dealer told me they believe it was coming from that, the service adviser had them tighten everything but still there. I asked to maybe put some kind on heat resistant material in between the parts that seems to rattle but they say since the pipes on the exhaust are too big they can not squeeze anything in there. I plan on taking the car to a muffler shop instead.

[OF Hero]

Thanks for all the replies.

I got out of work late yesterday and wasn't able to get over to the dealership. That being said, drove it home exclusively with the exhaust in dynamic and no further "rattle" last night nor this morning. Also sort of a related question, I know with some of the C6 models the car would not remember the individual drive settings on start up, and you'd have to switch over to auto/comfort and back to individual for your actual true individual settings to kick in. Is that still the case?

[ichi d]

Bump. Any solutions for this yet? At first I thought it was my epl Tune but now I'm starting to hear this rattle under light load at low rpms. Doesn't do it often but it's there from time to time. Car is stock tuned right now.

[RAF_S7]

It could be an issue with the catalytic converter or exhaust. A loose baffle plate somewhere.....

[Rubenders]

I am having the same problem with 2016 s7. Any solution?

[Audisthesia]

2016 S6 has a valve on each side FYI. They are in different locations, but there is one on each side. Drivers side is pre muffler, passenger is post muffler.