Mercedes-Benz E350 persistent oil leak from engine area on Mercedes-Benz E350

Some Mercedes-Benz E350 owners report experiencing persistent oil leaks from the engine area, often attributed to faulty seals and degraded gaskets. These leaks can also stem from issues with the oil separator and cam plugs, particularly the 30mm and 65mm cam plugs, which are known to be common leak points. Additionally, in engines like the M276 and M278, oil leaks from the camshaft adjuster magnets/solenoids and camshaft position sensors can impact various components, including the engine wiring harness and ECU. Some owners find that oil leaks travel down and soak the transmission bell housing due to improperly sized oil filter o-rings or worn o-rings around the oil filter housing, as well as leaks around the valve covers. To effectively address these issues, it is recommended that owners have a thorough inspection conducted by a qualified mechanic to accurately identify and resolve the source of the leak.