braincell38

I have a 2016 S6 with sports exhaust that has a very annoying buzzing rattle that happens about 1 second after the engine fires. It sounds to me like the active exhaust flap before the muffler on the driver side is actuating and rattling. It can happen during any startup but seems to be more frequent after the car has been sitting for 8hrs or longer and the exhaust is cold. The dealer had it for days and claims they cannot reproduce it of course. Has anyone had this issue and know a solution?

gk1

It is not an issue. My 2015 S6 makes the exact same noise since new (no sport exhaust in 2015) I believe it is a transmission solenoid of some sort buzzing up soon after startup. Or really it cold be any number of solenoid/actuator in this spaceship, not just from the transmission.

That may not make you feel better if the noise really bothers you, just letting you know it has been normal to me since day 1.

jsilas

My 2016 has done this from new, with and without original sports exhaust. No worries.

braincell38

Is your buzzing also intermittent? I would think if it was a solenoid, it would happen consistently and at the same loudness level. Sometimes my buzzing sound is barely noticeable and other times it's quite loud like in the video clip.

CHIO

its normal

elp_jc

Thankfully my 2018 doesn't do it. At least not yet. Ha ha. But yes, it'd annoy me too.

m444

I don't have the buzzing, but I do have a rattle on cold startup, when I back the car out the garage, which sounds like an old 1960s style loose heat riser valve (example below).