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.
Specifications
| 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.
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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