335d XDrive Engine Noise 1500-2000 RPM

[John K]

I was wondering if anyone might be able to help diagnose a problem I’m having.

I own a 2014 335d M Sport XDrive, and there’s a loud engine roaring noise that happens only between 1500-2000 revs, when pulling away from a standstill as the car goes up through the gears. It literally starts at 1500 revs and stops at 2000 revs.

If the cars in neutral and I rev, it doesn’t happen at all, only when pulling away.

Does anyone have an idea what could be causing this?

Thanks in advance,
John.

[Deranged Rover]

Can i get in first with the "it's the tractor engine under the bonnet" answer?

[sortedcossie]

If you stand in front of the car with the bonnet open, look down to the right where the altenator is. You'll see a squarish plastic pipe that runs to the front panel - there is a connection with a kind of fabric to deaden noise. Mine was making a kind of roaring racket under load when cold, that pipe had come slightly disconnected. It's happened a few times since, worth a quick look.

[John K]

Thanks, I will have a look for that 👍