Mercedes OM615 diesel engines have been manufactured since 1967 and are still being assembled in third-world nations despite several improvements. The Mercedes W115 and W123 passenger cars, minibuses, trucks 207D, 307D, and 407D, as well as their modifications, were equipped with versions 2.0 l and 2.2 l.
The engine is situated longitudinally, or in the direction of motion. The engine cylinders are housed in a unique cast iron block. The cylinder walls may be bored if there is significant wear, in which case repair pistons with the appropriate diameter must be put in.
A crankshaft supported by main bearings is located at the bottom of the cylinder block. Connecting rods and connecting rod bearings link the crankshaft to the pistons. An oil sump, which holds oil for engine cooling and lubrication, closes the lower portion of the block.
The top of the block is where the cylinder head is fastened. On the right side of the head are the intake and outlet manifolds. The crankshaft uses a chain to drive the camshaft, which is positioned in the middle of the head.
Specifications
| Engine’s type | diesel |
| Start of release | 1967 |
| Power, kW (hp) | 40 (55) 44 (60) |
| Displacement, cc | 1988 2197 |
| Number of cylinders | 4 |
| Number of valves | 8 |
| Torque output, Nm | 113 126 |
| Compression | 21:1 |
| Cylinder bore, mm | 87 |
| Piston stroke, mm | 92.4 |
| Crankshaft bearings | 5 |
| Configuration | inline |
| Fuel type | diesel fuel |
| Combustible mixture supply | direct injection |
| Turbine | suction pump |
| Cylinder head | SOHC/OHC |
| Timing mechanism | chain |
| Timing | rocker arm |
| Cooling | water |
The chain is always properly tensioned thanks to the hydraulic tensioner. The camshaft drives the vertically positioned timing valves via special levers.
An oil pump at the front of the oil sump, powered by an intermediate shaft, lubricates the engine. The crankshaft uses the camshaft drive chain to drive the intermediate shaft, which is situated on the left side. Through holes and lubrication channels, oil from the oil sump is delivered to the cylinder mirrors, camshaft bearings, and crankshaft bearings.
A V-belt-driven pump located at the front of the engine provides engine cooling while also powering the generator.
A high pressure fuel pump that is chain-driven from the crankshaft provides fuel. A mechanical fuel pump provides fuel to the injection pump. The injection pump’s regulator controls how much fuel is injected into the cylinders based on the accelerator pedal’s position. Injectors are used to supply fuel to each cylinder’s vortex chamber at specific times.
Frequent problems of OM 615
The exceptional endurance of Mercedes diesels was well known. These drivetrains are incredibly dependable and have a high mileage capacity. Nevertheless, there are drawbacks as well:
- Strong vibrations and noisy operation;
- leakage from the stuffing box at the back end of the crankshaft;
- a 200–250 thousand kilometer timing chain;
- and a malfunctioning fuel pump boost pump due to worn seals.
Explanation of marking
| OM | Heavy Fuel Oil (Diesel) ICE |
| 615 | Engine type: in-line |