2026-07-22 · 5 min read
Mercedes-Benz C-Class — 漏油问题
Common C-Class Oil Leak Points by Generation
- W204 M271: valve cover gasket — weeping at rear of engine; camshaft adjuster O-rings — front of engine drip
- W205 M274: valve cover gasket and oil separator hose crack — creates blue smoke under hard acceleration
- W206 M264: rear main seal and turbo oil feed banjo bolt — inspect at oil change
Diagnosis and Repair Cost
Always clean the engine with a degreaser first, then run it to identify the active leak source. Valve cover gasket. Oil separator hose. Rear main seal (labour intensive).