I have had a good search and haven't come across a noise like this. I have only noticed it a couple of times and thought I would post a video to see if it is a known problem?
Both times I have heard it the car has been warm, and I can only really hear it at idle, but it stays with revs (just the engine, covers noise). It doesnt seem to be linked to revs.
It is coming from the left hand side and not from the right (as you look at the engine).
Importantly, if I turn the car off and on straight away it stops.
To me it sounds like a vibration or possibly air passing a seal.
Any help appreciated!!!!!!!!!
N55 Manual car with 10k miles.