Mercedes Workshop Manual Om646 Engine ((full)) Jun 2026

Carbon buildup is common in diesel engines. The manual shows you how to remove the manifold and clean the swirl flaps to restore lost power.

Exact voltage and resistance values for the Crankshaft Position Sensor (CPS), Camshaft Position Sensor, Mass Air Flow (MAF), and Manifold Absolute Pressure (MAP) sensors.

Reinstall the drain plug with a new crush washer. Torque to 30 Nm. Mercedes Workshop Manual Om646 Engine

Rotate the crankshaft slowly by hand to feed the new chain through the system until it loops completely.

Operating at up to 1,600 bar for better fuel atomization. Carbon buildup is common in diesel engines

| Category | Specification | | :--- | :--- | | | 2002 – 2010 | | Configuration | Inline 4-cylinder | | Displacement | 2.1 L (2148 cc) | | Bore x Stroke | 88 mm × 88.3 mm | | Block Material | Cast Iron | | Head Material | Aluminum Alloy | | Valvetrain | DOHC, 4 valves per cylinder, hydraulic lifters | | Compression Ratio | 18.0:1 (original); 17.5:1 (EVO) | | Fuel System | Common Rail Direct Injection (Bosch CP3 or Delphi) | | Injection Pressure | Up to 1600 bar | | Turbocharger | Variable Geometry Garrett GTA1852VK | | Emissions | Euro 4 (Euro 5 for some EVO variants) |

A high-quality workshop manual—such as the —includes step-by-step procedures. A. Engine Management and Diagnostics Reinstall the drain plug with a new crush washer

: Detailed methods for delinking and relinking the chain using specialized tools, ensuring correct timing marks are aligned. Fuel System

Grind open a link on the old chain. Rivet the new chain to the old one.

Remove the oil filter cap from the top engine bay using a 32mm socket.