Front Cylinders also can have Valve Issues, perhaps more common than cylinder scoring.
Video to replace camshaft position sensors: • Change Camshaft Position Sensors to P...
Video about Airmatic DIY Diagnostics and Fixes • Mercedes Airmatic Suspension Troubles...
Forum posting about valve issues and cylinder scoring: https://mbworld.org/forums/glclassx...
Some common issues on the M278 and M157 engine as reported by forum users on mbworld and across facebook.