2015 s7 humming noise at stop, when applying brake, and sometimes when driving

[Mykohph]

Hi guys. I was hoping to get some help to see if anyone could diagnose the issue.

As the title states, I have an Audi s7 2015 just purchased cpo with 13k miles. It’s got a weird intermittent humming sound that comes and goes. I hear it when I’m at a complete stop idling, when I’m braking, and rarely as I drive.

I’ve had days where I don’t hear a thing and then some days when I hear it often as I drive around town. It’s only been at the dealership for a short time frame but I’d like to see if anyone has any suggestions as to what is causing this sound. Thanks!!

Below is the YouTube for the sound when I’m at a red light.

https://youtu.be/4FNmJGO_xtA

[wwhan]

Have looked in the back seat to see if you have a passenger? ghosts?

[Mykohph]

Have looked in the back seat to see if you have a passenger? ghosts?

Lol if it was only that. It would make for an interesting car.

[elptxjc]

There's a similar noise when the A/C compressor is working. Didn't sound like that on your video, but it could be your phone. Try turning A/C on and off and see if it stops. If not, then I have no idea what it could be. Good luck.

[AutoTalent]

Lol if it was only that. It would make for an interesting car.

At least they wouldn't weigh anything haha.

Sounds interesting though, would like to know what caused it when you get it fixed.

[wwhan]

I do find the low speed Heat/AC fan motor noise to be annoying, maybe that is why it likes run full blast most of the time.

[dspl1236]

I have the exact same on my 3.0T A6. Been driving me nuts. I thought it was wheel bearings...so I replaced those. Now I think it is the rotor howling from the ridges on the pads just riding on them. Brakes are the next task.

[Mykohph]

The sound is also there when the air conditioner is off. It’s been at Audi for the past 5 days. They said they’ve narrowed it down to crank box or fans but it’s so intermittent they haven’t been able to catch it when the hood is open.

It’s been escalated with Audi and my rep says we should hear something by Monday for a fix. I’ll keep you guys updated.

[Frenetic]

When you say crank box, do you mean the crankcase ventilation or PCV?

If it is that, maybe the sound you’re hearing are the precursors to the more loud whistling that is heard after it has fully degraded.

[Mykohph]

When you say crank box, do you mean the crankcase ventilation or PCV?

If it is that, maybe the sound you’re hearing are the precursors to the more loud whistling that is heard after it has fully degraded.

I don’t remember exactly what he said but crankcase ventilation sounds about right. Then again my friend just had his pcv replaced due to loud whistling. I’ll let you know when I get word from the dealer.

[Mykohph]

just an update - they couldn't figure out what it was and want me to just drive it until its a consistent sound -_-