[Kamigouki]

Recently picked up a 2017 340i, and this is driving me insane. It starts around 40 mph, and gets louder with speed, there is an awful whistling noise on the driver's side.


I have already tried reseating all the gaskets around both doors, taped over every seam on the driver's side, and I am out of ideas. Has anyone had this problem, and how did you fix it?


I already took it to the dealer, and they said they could find anything and still charged me for diagnostics.

[Mikej0h]

I would check whether the bottom guard plates (engine) on the front and left middle (fuel filter) are attached properly.

[IAmATeaf]

Isn’t the door mirror renowned for whistling if it’s not seated properly?

[zibbit]

I had a problem similar to yours. In my case, it turned out to be one of the firewall plugs wasn't sealed correctly underneath the cowl. The dealer replaced both front bumper camera cables on warranty and routed both the new wires incorrectly causing a whistling and humming noise which sounded like it was coming from the windshield or door glass over 90 kmh.

If the previous owner had a JB4 installed, generally the cable that plugs into the OBD port comes through the same grommet. That grommet might not have been sealed or replaced before selling the car.

[Kamigouki]

Originally Posted by zibbit

I had a problem similar to yours. In my case, it turned out to be one of the firewall plugs wasn't sealed correctly underneath the cowl. The dealer replaced both front bumper camera cables on warranty and routed both the new wires incorrectly causing a whistling and humming noise which sounded like it was coming from the windshield or door glass over 90 kmh.

If the previous owner had a JB4 installed, generally the cable that plugs into the OBD port comes through the same grommet. That grommet might not have been sealed or replaced before selling the car.

Do you have any pictures that could help me find where you're talking about?

Originally Posted by Mikej0h

I would check whether the bottom guard plates (engine) on the front and left middle (fuel filter) are attached properly.

Would this cause a whistling noise that seems to come from the window? the sound either disappears or I can't hear it anymore when I open the driver's window, even if only a little.

[zibbit]

Originally Posted by Kamigouki

Do you have any pictures that could help me find where you're talking about?

Pretend like you're trying to access the brake master cylinder to check your brake fluid; and pop off the under-hood cowl that's held in place with three 10mm 1/4 turn fasteners. In there you'll see a rubber firewall plug just outboard of the brake master cylinder. Verify that the 22mm plug (p/n 51-71-1-855-009) is in good shape.

[Kamigouki]

Originally Posted by zibbit

Pretend like you're trying to access the brake master cylinder to check your brake fluid; and pop off the under-hood cowl that's held in place with three 10mm 1/4 turn fasteners. In there you'll see a rubber firewall plug just outboard of the brake master cylinder. Verify that the 22mm plug (p/n 51-71-1-855-009) is in good shape.

Thank you for the awesome picture, I will give this a look when I have some daylight.