Mercedes Workshop Manual Om646 Engine Direct

If you are planning a timing chain replacement on an OM646 (e.g., in a W203 C220 CDI), do not proceed without the manual. The chain is at the transmission side of the engine. This often requires:

One tooth off equals piston-to-valve contact and a scrap cylinder head. The workshop manual provides the only safe path through this job. Mercedes Workshop Manual Om646 Engine

| Code | Power | Torque | Application | |------|-------|--------|--------------| | OM646.981 | 82 kW (110 hp) | 250 Nm | Sprinter 211 CDI | | OM646.963 | 100 kW (134 hp) | 340 Nm | C-Class (W203) | | OM646.961 | 110 kW (148 hp) | 340 Nm | E-Class (W211), C-Class (W204) | | OM646.951 | 125 kW (168 hp) | 400 Nm | C350 CDI (twin turbo - rare) | If you are planning a timing chain replacement

You have three legitimate options:

Warning: Free PDFs on forums are often incomplete, missing crucial safety steps (e.g., high-pressure fuel system de-pressurization), or are for the wrong OM646 variant (e.g., 646.963 vs 646.811 have different injection systems). One tooth off equals piston-to-valve contact and a