2012 F20 116i - N13 engine rattle/growl. - Vacuum pump?

[mcbonio]

So I feel a bit of a hypocritical mug posting this, after years of advising folk on here NOT to buy 4 pot BMWs.. :hihi

My wifes 116i N13 (43k FSH) engine has developed a cyclic rattle/growl on a fast idle, the cyclic rattle/growl can be felt at the back of the cylinder head on the vacuum pump area at around 2.5k revs. On and off the accelerator the engine feels a bit lumpy, kinda like a vacuum leak - on idle engine is stable.

Car has no oil or water usage, ISTA diagnostics are showing nothing at fault. I don't suspect timing chain, guides or tensioner as they are on the front of the engine, it also has no vanos system.

https://youtu.be/2FAcTmQiys4


I think it's the vacuum pump, as there really isn't anything else on the back of the cylinder head. Anyone have an experience on the N13 116i engine?