Cause of a 'whirring noise' - E46 320d

[TREMAiNE]

A colleague has a 2006 E46 320d which is on about 150k.

He's said that it's started making a whirring noise at around 30mph.
The noise doesn't get any louder as you go faster.

It doesn't seem to occur below 30mph, and doesn't occur if you're stationary revving the car.

I presumed wheel bearing or something but he seems to not think it's that.

Any ideas?
I don't know much about common faults on E46s so maybe there is something blindingly obvious to BMW gurus as to what it is.

[d_a_n1979]

TREMAiNE said:

A colleague has a 2006 E46 320d which is on about 150k.

He's said that it's started making a whirring noise at around 30mph.
The noise doesn't get any louder as you go faster.

It doesn't seem to occur below 30mph, and doesn't occur if you're stationary revving the car.

I presumed wheel bearing or something but he seems to not think it's that.

Any ideas?
I don't know much about common faults on E46s so maybe there is something blindingly obvious to BMW gurus as to what it is.

Any ideas where it's coming from (front axle, rear axle, front of engine etc)?

Could be a wheel bearing, but that's usually a low rumble. Have the brakes checked for a sticking caliper or something like a stone wedged between the disc and backing plate etc

Check the viscous fan clutch too for peace of mind

[TREMAiNE]

d_a_n1979 said:

Any ideas where it's coming from (front axle, rear axle, front of engine etc)?

Unfortunately not.

I'll take it for a drive later and have a listen myself to try and get more info.

[njw1]

Propshaft centre bearing possibly, any vibration on the over-run when slowing down?