Mercedes Workshop Manual Om646 Engine Verified Jun 2026

The OM646 relies on high-pressure common-rail technology operating at up to 1,600 bar.

While the OM646 is known for a robust timing chain, the manual provides the exact "stretch" tolerances and replacement steps.

Common Rail Direct Injection (CDI) with Bosch solenoid or piezo injectors. Mercedes Workshop Manual Om646 Engine

MB 325.0 (Blue/Green) or 325.6 (Pink/Violet) depending on year; mixed 50:50 with distilled water.

Utilizing high-pressure fuel delivery for better atomization and reduced noise. MB 325

Turbocharged with Intercooler (VNT / VTG technology)

The Mercedes-Benz OM646 engine is a cornerstone of the German manufacturer’s "four-cylinder diesel dynasty." Produced from 2003 to around 2010, this 2.1-liter (2148cc) common-rail turbodiesel succeeded the legendary OM611 and preceded the OM651. Found in everything from the C-Class (W203/S203) and E-Class (W211) to the Sprinter van and Vito, the OM646 is renowned for its robustness, fuel economy, and long service life. Found in everything from the C-Class (W203/S203) and

Indicates a drop in high-pressure fuel supply. Check the fuel quantity control valve on the high-pressure pump, the rail pressure sensor, or look for excessive fuel return leak-off from a failing injector.

: Varies between 220 Nm and 400 Nm , depending on the specific model and tuning.

Utilizing an injector seat cutter tool to ensure a perfectly flat surface for the new copper washer. EGR Valve and Intake Manifold Swirl Flaps

With the manual: You follow the "GF07.35-P-2000T" procedure. You turn the engine to 40° ATDC (after top dead center). You lock the crankshaft with tool (602 589 00 21 00). You loosen the camshaft sprockets. You break the old chain and pull the new one through. You reassemble and time it perfectly.