Rattle noise + vibrations coming from the rear

[ManuD]

Hi guys,

I own a 98 Boxster since now almost 5 years. No major problem so far. I replaced the air flow sensor and the coolant fluid reservoir. Nothing really serious until (I hope not) now...

I recently opened my engine compartment and I found out that my engine was making some weird "grindy" noise and was vibrating at 2500 RPMs and at 3500 RPMs. These vibrations are so strong that they can be felt while engine braking.

I had the Porsche mechanic checking that out and he mentioned that the problem could come from either a bearing from the crankshaft or a faulty chain tensioner. However, he wanted to investigate further. As he was performing the usual maintenance on the car, he found out that the used oil had some small aluminium and bakelite part in it. He diagnosed it as an issue with the variocam unit. He fears that the chain is rubbing the cylinder head (hence aluminium pieces in oil) and that the bakelite comes from the variocam unit.

The car runs really well! Good accelerations, no stall or loss of power. No CEL and No P-codes reported.

Any ideas? Thoughts?

Thanks

ManuD