I having some trouble with a 2009 cooper S. While trying to rectify a periodic combustion gas smell and potential overboost issue I discovered this issue.

Note that my cell phone is amplifying all noises and it’s not as loud as it’s sounds in the clip. It is faintly audible with the filler cap in place.

I’ve pulled the valve cover and plugs and checked the timing chain / tensioner, valve clearance / operation, PCV system, rough check of con rod play.
I’ve stethoscoped turbo / wastegate, timing cover, all over the head, vanos, intake, exhaust man, block. Nothing stands out
Sound appears to be centrally located in the engine but that maybe just amplified / directed by the valve cover? I really want it to be timing chain / guide but nothing is pointing that way. Are there pcv baffles in the vc that could sound like this?

I should note that the car runs fine other than the smell and boost issue which I think / hope is a bad breather hose.

Any thoughts / help is appreciated

Thank you.

 

Your list does not explicitly mention the vacuum pump. ;-)
While I can clearly hear the vacuum pump in your clip, I unfortunately can't tell whether it sounds "healthy" or not. The vacuum pump is also audible in mine.

 

Thanks for that, it is completely possible that it’s the vac pump. I did scope it but didn’t register to me what it was. I need to investigate this further.
Thanks again