Engine Mercedes OM628

Engine Mercedes OM628

The OM628 engine is an 8-cylinder diesel internal combustion engine in a V-configuration with direct injection and turbocharger, developed and produced by Daimler-Benz for use in Mercedes-Benz mid-range passenger cars. OM 628 debuted in the summer of 2000 in the Mercedes S 400 CDI S-Class (220 series).

Also used in the E-Class (W 211) and in the G-Class and M-Class SUVs (W 163). The OM628 engine was Daimler-Chrysler’s answer to the rival’s Audi A8 and BMW 740d with their 8-cylinder diesels. The engine block and cylinder heads are made of aluminum alloy by sand casting.

Specifications OM 628 DE 40 L

Displacement 3996 cc
Fuel system Common Rail
Power 250 – 260 hp
Torque output 560 Nm
Cylinder block V8, aluminum
Cylinder head 32v, aluminum
Cylinder bore 86 mm
Piston stroke 86 mm
Compression ratio 18.5
Engine features intercooler
Hydraulic compensators yes
Timing drive chain
Phase regulator no
Turbocharging two GT1749V
Recommended engine oil 10.5 liters 5W-30
Fuel type diesel
Euro standards Euro 4
Engine lifespan 300 000 km

Engine Mercedes OM628 under the hood

Frequent problems

The OM628 engine is famous for its many problems and the difficulty in fixing them:

  • the main troubles are caused by constantly pouring injectors, as well as fuel injection pump failures;
  • the motor tends to coke quickly, first of all it concerns the USR;
  • prolonged overheating can lead to scuffing in the cylinder liners;
  • on runs of 150+ thousand km, many owners have encountered cylinder head cracks.

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