Originally Posted by ILUVMILS

FWIW, there’s an MB Service Bulletin from July 2003, that recommends replacing the engine mounts to cure a “piston slap like sound” on certain V8 powered MB’s. I realize the justncases’ car has the M112 V6, but I’ve fixed many “engine knock” complaints by replacing worn engine/transmission mounts.

So GM has the market cornered on piston slap? I’ve replaced dozens of “fitted blocks” (new engine blocks with fitted pistons), over the last few years due to piston slap. By the time the driver hears it, the piston skirts have made a mess out of the cylinder walls.