The OM639 has three cylinders and a 1,493 cc in-line diesel engine. and the water cooled. It has 68–95 horsepower. Power Index: 39 horsepower per liter of volume. created the engines for Mitsubishi Motors and Mercedes-Benz.
Japanese Mitsubishi vehicles were equipped with the OM639 engine. The motor was manufactured between 2004 and 2006. The OM639’s design is similar to that of a vintage Mercedes engine:
- timing chain;
- the idler camshaft drives the injection pump, which is connected to the cylinder head;
- the cylinder head has two camshafts;
- each cylinder has four valves;
- and there are hydraulic lifters.
Engine Modifications
- OM639 DE15 LA R 50 kW (68 HP)
- 70 kW (95 HP) OM639 DE15 LA
Specifications
| Manufacturer | Mercedes Benz and Mitsubishi Motors |
| Also called | OM 639 |
| Start of production | 2004 |
| Configuration | inline, 3-cylinder water-cooled |
| Number of cylinders | 3 |
| Number of valves | 12 |
| Piston stroke, mm | 92 |
| Cylinder bore, mm | 83 |
| Displacement, cc | 1493 |
| Power output, hp | 68-95 |
| Torque output, Nm / rpm | 210/1800 |
| Euro standards | Euro 4 |
| Compression ratio | 18:1 |
| Combustible mixture supply | direct injection |
| Cylinder head | DOHC |
| Timing mechanism | chain |
The OM639 has a balance shaft that is bolted to the side of the unitized block and housed in a separate housing to dampen first order inertial forces. The oil pump chain powers the balancer, which rotates in the opposite direction from the crankshaft at the same speed. Oil is used to lubricate balancer bearings. Its body is also equipped with an oil filter and a heat exchanger.
The four-cylinder OM640 engine serves as the model for the OM639 engine. The OM639 is essentially a simplified version of the OM640 engine, which includes parts like:
- Gas recirculation,
- four valves per cylinder,
- turbocharging,
- intercooler,
- cast iron block,
- aluminum cylinder head,
- Euro 4 compliance,
- dual-mass flywheel,
- and Bosch’s second-generation common rail injection system.
These diesels have exactly the same injection pumps and pistons. Unlike its predecessor, the OM639 engine is installed nearly vertically in cars and lacks a fourth cylinder. For the OM639 diesel engine, compact (short) injectors that injected fuel in two stages at a pressure of 1600 bar were also developed.
OM639 engine problems and breakdowns
The engine is not very good. There have been instances of significant wear, which led to the engine being either replaced with a contract engine or sent for an overhaul.
If the engine won’t start, you should inspect the high-voltage wires and starter. Terminals and wires corrode and shatter. The starter is not very strong.
Oil Separator Issues: The engine’s state is indicated by how clean the oil separator housing is. It becomes clogged by resinous deposits, which raises the crankcase gas pressure. They impede the oil scraper rings’ ability to function while supporting the pistons. The combustion chamber’s temperature rises as a result of the burning oil, and carbon deposits build up on the pistons and valves. Additionally, the cylinder head is having issues.
Turbine issues: OM639 has a Japanese IHI RHF3 turbine installed. Behind it, a wedging of the bypass valve was observed. In this situation, the engine might not run at maximum power and instead use more power. Additionally, the temperature in the combustion chambers may be adversely affected by the IHI RHF3 turbine’s ability to force oil into the intake.
Issues with the pipe connecting the turbine to the intercooler: frequently, the pipe breaks from the turbine’s side, and the cuffs at the ends deteriorate. This is evident from the oil fogging up. Air “escapes” through a rupture or leaky seals.
EGR valve issues: Soot and oil buildup has caused the valve to become stuck open, depriving the engine of a substantial amount of air. Black smoke emerges from the outlet as a result of the fuel not burning entirely.
Cylinder head issues: A common issue with the OM639 diesel engine is the development of cracks in the cylinder head, which is caused by an increase in temperature in the combustion chambers against the backdrop of a significant oil consumption that has started.
Explanation of OM639 marking
| OM | Heavy Fuel Oil (Diesel) ICE |
| 639 | Engine type: 3-cylinder in-line. |