325 whining noise?

[bmw9818]

Any ideas? Doesn't sound like it's coming from the back more the front, it's had new wheel bearings

And it's only louder and pronounced when cold?

[iceox]

sounds like the vtech kicking in yo.

sounds engine related, doesnt really sounds like bearing etc. could it be exhaust blowing. the manifold can rust creating pin holes that sound a bit weird

[e30den]

Cold diff ? may seem worse due to the weather getting a bit on the cold side.

[capnmchl]

Sounds like my gearbox and diff when they're cold.