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 diesel R6-family includes: OM603, OM606, OM613, OM648, OM656.
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.
Specifications
| Production years | 2002-2006 |
| Displacement, cc | 3222 |
| Fuel system | Common Rail |
| Power output, hp | 177 (OM 648 DE 32 LA red or 280 CDI) 204 (OM 648 DE 32 LA or 320 CDI) |
| Torque output, Nm | 425 (OM 648 DE 32 LA red or 280 CDI) 500 (OM 648 DE 32 LA or 320 CDI) |
| Cylinder block | cast iron R6 |
| Block head | aluminum 24v |
| Cylinder bore, mm | 88 |
| Piston stroke, mm | 88.3 |
| Compression ratio | 18.0 |
| Features | DOHC |
| Hydraulic lifters | yes |
| Timing drive | chain |
| Phase regulator | no |
| Turbocharging | VGT |
| Recommended engine oil | 5W-30 |
| Engine oil capacity, liter | 7.5 |
| Fuel type | diesel |
| Euro standards | EURO 4 |
| CO2 emission, g/km | 183 – 204 |
| Fuel consumption, L/100 km (for Mercedes S 320 CDI 2004) — city — highway — combined |
11.0 5.8 7.7 |
| Engine lifespan, km | ~400 000 |
| Weight, kg | 240 |
The engine was installed on:
- Mercedes E-Class W211 in 2002 – 2006;
- Mercedes S-Class W220 in 2002 – 2006.
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.
Disadvantages of the OM648 engine
- 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.
