Mercedes-Benz OM602 engine

The successor of the OM617 engine family was the newly developed straight-5 diesel automobile engine OM602 from Mercedes-Benz used from 1980s up to 2002. With some Mercedes-Benz 250D/E250D diesels exceeding 500,000 or 1,000,000 miles, it is considered to be one of the most reliable engines ever produced, a success which is only comparable with the famous OM617 engine.

The 5-cylinder OM602 was succeeded by the four-valve engine OM605 (E250D 20V) and later the OM612 and OM647 with turbocharger and common rail direct injection (C/E/ML 270CDI).

The engine

The Mercedes OM602 engine is a 5-cylinder diesel engine of 2497cc or 2874cc. The 2874 cc (2.9 L) was used in the 310D and 410D Mercedes-Benz T1 and the Phase 1 Mercedes Sprinter vans (where it was modified for direct injection), the Ssangyong Musso and Korando range and even in the 1996–1999 models of the E-class. It was available in either naturally aspirated or turbocharged variants with two valves per cylinder.

The camshafts and injection pump are driven by duplex chain from the crankshaft. A separate single-row chain drives the oil pump. The camshaft operated the valves via hydraulic bucket tappets; valve clearance adjustment is automatic.

On many OM602 engines fuel injection is indirect. A Bosch PES in-line injection pump is used, with a mechanical governor and vacuum-operated stop control. The pump is lubricated by a connection to the engine oil circulation and the fuel lift pump is mounted on the side of the injection pump.

Some later versions of the 2.9 L capacity unit use a Bosch VE-style rotary distributor injection pump with electronic control and have a significantly different combustion chamber as they use direct injection.

Preheating is by glow plugs with automatic control of preheating time.

Versions of OM602 Mercedes 5-cylinder diesel engine