Beyond head bolts, owners flag camshaft and lifter wear ('cams/lifters eating each other') and camshaft timing-gear replacement as a distinct M156 failure mode. The recurring advice is diligent, high-quality oil changes, since the top-end wear is tied to lubrication of the cam and lifter parts. …
Cams, lifters, and top-end wear — the other way to kill an M156
Mercedes-Benz R63 AMG (W251) · mechanical