odd whistle

[bosers]

Here's a tricky one, my 325i touring has developed a high pitched whistle that seems to be coming from the engine bay. It's not very loud and seems to only happen when engine under load or when pressing the accelerator at certain speeds.It's difficult to check as it only seems to happen under load. I don't think I have any air leeks and can't think what else to look at. Any ideas?

[Brianmoooore]

A hole in the big rubber pipe between the air filter box and the engine or (more likely) a failed inlet manifold gasket.
Get a short length of garden hose, hold one end against your ear, and probe the other end around the joins between the inlet manifold and the head.

[bosers]

Thanks Brian, I'll give that a try.a˜Š