Noise from a clutch part

[Longitudinal4Cylinder]

I have an 2002 316i E46 facelift with the N42B18A 1.8 Litre DOHC engine. When the clutch is engaged in N and im sitting (or driving but this is an example only) i hear an noise similar to an bad release bearing and this whole time i thought it was one of those, but when you disengage the clutch, the noise remains there... (In another car it stopped when it was a bad bearing) It seems to slow down and speed up (the noise) when the engine is cold and i turn it drops rpm so the noise slows. The only time the noise stops is when i hold the clutch in gear or am just about to engage a gear... What would this be? Thanks in advance.

[Jaybmw]

Flywheel would be my first though but it shouldn't get louder or quiter. Best pop it to a specialist they'll know better

[Longitudinal4Cylinder]

Yeah i was thinking flywheel but 2 yesrs ago i had a Mazda 6 way a bad flywheel and as soon as you went past the clutch point the sound went out. So it may be a flywheel (hope not) but thanks anyway.