For M50TU and M52 engines, the Vanos piston bearings have axial play. This play shouldn’t be there. The camshaft engages this play back and forth as the cams compress and decompress the valve springs. At certain RPM ranges these movements can resonate and you get a rattle.

Of course all the pistons have loose bearings and it’s best to remove this on all the cars. Even if a car is not experiencing a rattle, the resonance and rattle can develop at any time.

The Vanos Rattle Repair kit includes a replacement bearing rings, which can be fitted to significantly reduce this play, thus stopping rattle and avoiding rattle becoming a future problem.

BS092 or BS093 required for installation, available to buy/hire separately.