F10 M5 - Rough Running/Hesitant between 1-2k RPM

[f10weston]

Morning all,

My 2015 LCI has recently developed two issues, one being a coolant leak behind the engine which I believe is the plate inside the bellhousing and I am arranging to sort, but more concerning at the moment (because I can't work out what is causing it) is a strange lack of power and rough running between 1-2k RPM when accelerating in a low gear.

The car idles smoothly with no misfiring, runs smoothly through the rev range in neutral, and pulls fine above 2k rpm in all gears, but if I accelerate at any point between 1-2k it judders and shakes the whole car and a weird pulsing grinding noise comes from under the bonnet (I think). Seems to only be when putting torque through the car at low revs.

No codes either, which is helpful! Wondering if the coolant leak is connected.

At a bit of a loss with this one, wondering if anyone has experienced anything similar and could advise where to look?

[M5Rick]

Have you checked the pcv's for oil blockage and the close by MAF's for oil mist contamination, it's obvious but have you checked the engine oil level.

[MBMW]

Check you valve stem seals. Borrow a camera (borescope) and look for oil inside combustion chamber.

Had N63tu with exact symptom, seals were leaking. Good luck