M50 engine noise
I have had a noise issue for several years and which is getting progressively worse as you might expect.
Nothing when cold but when hot at low revs under light load what I can best describe a a dull knock. Under heavy load eg a fast start it does not exist! In any event the noise goes away at higher revs.
With a stethoscope it seems to be from the timing chain area but it is not what I would regard as chain noise.
Various dealers have listened but no ideas except to disconnect Vanos which I did with no effect.
I thought about oil viscosity change with temperature perhaps related to chain tension but this is spring loaded!
What about hydraulic tappets? but location does not stack up
I intend to remove the cam cover to have a look but don't expect to see anything amiss.
There are no performance or any other issues.
Any thoughts or suggestions would be appreciated