Mercedes-Benz E300 oil pump wiring harness and crankcase ventilation valve replacement completed on Mercedes-Benz E300

Some Mercedes-Benz E300 owners report experiencing issues during the replacement of the oil pump wiring harness and crankcase ventilation valve, including high repair costs due to expensive parts and labor. Additionally, while the crankcase ventilation valve/hose assembly may be covered under an extended warranty, this coverage is only applicable if specific fault codes are present. Owners also note the importance of replacing the entire crankcase vent line assembly to maintain engine reliability, as it is covered under a Mercedes-Benz Emission Extended Warranty for up to 15 years or 150,000 miles. Furthermore, some owners have encountered problems with oil leaking from the camshaft position sensors into the engine harness, which can damage internal wiring and other components. To mitigate risks, it is advised to inspect the wiring loom at the camshaft adjusters and consider adding a Mercedes Sacrificial Wiring Pigtail to prevent oil from wicking into the harness. Following manufacturer guidelines and ensuring proper diagnosis of faults is crucial for a successful repair.