Engine Mercedes OM648

Engine Mercedes OM648

The 3.2-liter 6-cylinder inline engine Mercedes OM648 was assembled from 2002 to 2006 and was installed only on the E-Class in the body of the W211 and the restyled S-Class in the body of the W220. In addition to the usual version of 204 hp, a modification with a power reduced to 177 hp was offered.

The motor was produced in two versions – 648.960 (installed on S320CDI) and 648.961 (installed on E320CDI and E280CDI). Moreover, the working volume was the same everywhere – 3222 cc.

The internal designation of the engine is OM 648 DE 32 LA. With an OM648 working volume of 3222 cc, its power is 204 hp for the 320CDI versions and 177 hp for the 280 CDI version. In both cases, the maximum power is achieved at a speed of 4200 rpm. The maximum torque is 500 Nm at 1800 rpm in the first case and 425 Nm at 1800-2500 rpm in the second.


Displacement, cc 3222
Power 130 kW / 177 hp at 4200 rpm
150 kW / 204 hp at 4200 rpm
Torque output, Nm (kg-m) at rpm 425 (43) at 1800-2500 rpm
500 (51) at 1800 rpm
Fuel type diesel fuel
Fuel consumption, L/100 km 6.9 – 7.7
Configuration inline, six-cylinder
Cylinder head DOHC
CO2 emission, g/km 183 – 204
Cylinder bore, mm 88
Piston stroke, mm 88.3
Valves per cylinder 4
Supercharger Turbine
Compression ratio 18

How the engine works

The engines operate with a VGT or VNT turbocharger. The boost pressure is up to 1600 bar. There are 2 camshafts on motors, the drive is carried out using a timing chain. There are 4 valves per cylinder, adjustable by pushers. There is an electronically controlled EGR valve. The control unit also controls the fuel pump, and the fuel is supplied metered.

Pre-injection, which means that a small portion of the fuel is burned before the main process. This makes it possible to heat the chamber, which contributes to a quick start and warm-up of the motor. Of course, the temperature regime and the pressure parameter are better maintained. Some modifications of these engines are equipped with a balance shaft rotating opposite the crankshaft at a higher speed.
Engine Mercedes OM648 under the hood

Disadvantages, breakdowns and problems of OM 648

  • the main diesel problems are related to the components of the common rail fuel system;
  • fuel shut-off valve and fuel rail pressure sensor often fail;
  • because of the burnout of the refractory washers under the injectors, the engine quickly cokes;
  • the reason for airing the system is usually the breakdown of plastic quick-release devices;
  • Variable intake manifold flaps often wedge due to carbon deposits.

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