[Schietgans]

Hi everyone,

Here's an interesting one. My friends and I can't figure out what is causing this high-pitched whining noise I hear while driving my 318i E93 2010 LCI (with the roof up). Link to sound clip:
https://record.reverb.chat/s/e5ZaeCDAk6DVwed1Feqr

As I describe in the sound clip, I accelerate to 60km/h, disengage the clutch and let go of the accelerator. This is on a relatively flat, straight road; weather is clear and dry. I don't hear it while standing still, seems to be coming from my rolling stock or drive train post clutch.

I also did a test where I stopped on a hill and let the car roll down from 0 to 40km/h. The noise started at around 10km/h and kept a similar volume. Also, speed and revs don't alter the pitch of the whine, and swerving from left to right repeatedly doesn't change the sound either.

This car has been serviced very regularly and doesn't have any defects as of this moment (that I know of). It's at 90.000km and approximately 16 years old.

Any ideas?

P.S. apologies if this is a known, well-described issue, but I couldn't find out anything about it online.