[Kail Wright]

Hi e90post,
This is a repost from UK technical forum, but since the engine (320i) is almost certainly not the cause, I might as well post it here.

When I drive my euro daily driver 320i (N43B20) I get this strange high pitched noise. I can't quite locate the source of it, but it might be from the back. It does go away when I slow down to below maybe 15mph, but above that speed it's (probably) always present. It doesn't go away when I press the clutch and it's not present when I'm stationary or rev the engine when stationary, so I assume it's not the engine. The noise occurs both when driving straight and when turning.
Has anyone got any idea what might be the root of this noise? The car had only done 44k miles.
Thank you for your answers.