Engine Mercedes OM628

Engine Mercedes OM628

The Mercedes OM628 engine is an 8-cylinder diesel 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).

The diesel V8-family includes: OM628, OM629.

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.


Production years 1999-2005
Displacement, cc 3996
Fuel system Common Rail
Power output, hp 250 – 260
Torque output, Nm 560
Cylinder block aluminum V8
Block head aluminum 32v
Cylinder bore, mm 86
Piston stroke, mm 86
Compression ratio 18.5
Features intercooler
Hydraulic lifters yes
Timing drive chain
Phase regulator no
Turbocharging GT1749V
Recommended engine oil 5W-30
Engine oil capacity, liter 10.5
Fuel type diesel
Euro standards EURO 4
Fuel consumption, L/100 km (for Mercedes ML 400 CDI 2003)
— city
— highway
— combined
Engine lifespan, km ~300 000
Weight, kg 275

The engine was installed on:

  • Mercedes E-Class W211 in 2002 – 2005;
  • Mercedes G-Class W463 in 2001 – 2005;
  • Mercedes ML-Class W163 in 2001 – 2005;
  • Mercedes S-Class W220 in 1999 – 2005.

Disadvantages of the OM628 engine

Engine Mercedes OM628 under the hood
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 very quickly, especially the EGR;
  • 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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