Engine Mercedes OM604

Engine Mercedes OM604

The 4-cylinder diesel engine OM604 is the younger brother of the 5-cylinder OM605 and 6-cylinder OM606. Structurally, diesel engines Mercedes of the 602/604/605/606 series are very similar – they all have a cast iron block and aluminum heads with 4 valves per cylinder and mechanical injection pumps.

The OM 604 engine was produced in two versions: a volume of 1997 cc (from 1996 to 1998) and 2155 cc (from 1993 to 1998). Equipped with an EVE injection system (Elektronic Verteiler Einspritzpumpe) manufactured by Lucas. The latest versions were equipped with a Bosch pump – this system was called EDC (Elektronic Diesel Control).

Such a motor is called a vortex chamber, since during the working stroke the air swirls strongly when passing through the preliminary chamber. Fuel injection is also carried out here. Thus, the combustion of diesel fuel is carried out in a special type of chamber located in the cylinder head. The remaining gases rush into the cylinder, acting on the piston.


Manufacturer Mercedes-Benz
Also called OM 604
Start of production 1993
Cylinder block alloy cast iron
Fuel system direct injection
Configuration inline
Number of cylinders 4
Piston stroke, mm 86,6
Cylinder bore, mm 89
Compression ratio 22
Displacement, cc 2155
Power output, hp 74-94/5000
Torque output, Nm / rpm 150/3100
Fuel type diesel
Euro standards Euro 2/3
Engine lifespan, km
— official information
1 000

Pros and cons of the engine

The advantages of this engine include:

  • Reliability. Indeed, the motor is cast from cast iron, its piston does not experience excessive loads, easily withstanding the 600,000th run. With timely maintenance, the engine worked without capital and up to 1 million km;
  • Lack of electronics. There are no masses of breaking sensors and computers;
  • Not picky about fuel. Designed from 90s designs, this powertrain accepts any diesel fuel;
  • Cost effective. Compared to petrol counterparts, OM604 consumes much less;
  • Reliability.

Engine Mercedes OM604 under the hood

Frequent problems

  • The engine, like its brothers, is very afraid of overheating – if it overheats, it can move the block head, or it can burst.
  • Complexity of repair. The injection system is extremely difficult to restore.
  • The sensitivity of the injection system to the presence of water in the fuel.

Explanation of OM604 marking

OM Heavy Fuel Oil (Diesel) ICE
604 Engine type: 4-cylinder in-line.

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