The Mercedes OM640 or A-Class 2.0 CDI engine was produced from 2004 to 2012 and was installed only on the second generation of the A-class and the similar B-class compact van. This power unit essentially replaced the popular OM668 diesel engine with a volume of 1.7 liters.
The diesel R4-family includes: OM616, OM601, OM604, OM611, OM640, OM646, OM651, OM654, OM668.
OM640 engine is a 2.0-liter in-line 4-cylinder diesel engine with Common Rail direct injection and turbocharger in various power ratings.
The increase in displacement and the high ignition pressure required due to the increase in power, combined with the limited space in the engine compartment, did not allow the cylinder block to be made of aluminum. Therefore, the cylinder block of the OM640 engine is made of cast iron and does not have separate cast iron liners. The disadvantage of this is an increase in weight by 18 kg, but on the other hand, the engine noise level is reduced. The cylinder head is made of high-strength alloy aluminum and is equipped with 2 camshafts and 4 valves per cylinder. The valves are controlled by roller tappets with hydraulic compensators.
Interestingly, the OM640 is the base for the Thielert Centurion 2.0 aircraft engine. Also used as a base for the Austro Engine AE-300/330 aircraft engine in the Diamond DA-42 and DA-62 aircraft.
Specifications
| Production years | 2004-2012 |
| Displacement, cc | 1991 |
| Fuel system | Common Rail |
| Power output, hp | 82 (DE 20 LA red 160 CDI) 109 (DE 20 LA red 180 CDI) 136 – 140 (DE 20 LA 200 CDI) |
| Torque output, Nm | 180 (DE 20 LA red 160 CDI) 250 (DE 20 LA red 180 CDI) 300 (DE 20 LA 200 CDI) |
| Cylinder block | cast iron R4 |
| Block head | aluminum 16v |
| Cylinder bore, mm | 83 |
| Piston stroke, mm | 92 |
| Compression ratio | 18.0 |
| Features | EGR |
| Hydraulic lifters | yes |
| Timing drive | chain |
| Phase regulator | no |
| Turbocharging | IHI VV16 (DE 20 LA red 160 CDI) IHI VV16 (DE 20 LA red 180 CDI) BorgWarner BV43 (DE 20 LA 200 CDI) |
| Recommended engine oil | 5W-30 |
| Engine oil capacity, liter | 5.8 |
| Fuel type | diesel |
| Euro standards | EURO 3/4 |
| Fuel consumption, L/100 km (for Mercedes A160 CDI 2008) — city — highway — combined |
5.4 3.9 4.5 |
| Engine lifespan, km | ~280 000 |
| Weight, kg | 160 |
The engine was installed on:
- Mercedes A-Class W169 in 2004 – 2012;
- Mercedes B-Class W245 in 2005 – 2011.
Disadvantages of the OM640 engine
- This is a very reliable diesel engine with Bosch Common Rail and electromagnetic injectors.
- The main problems are caused by contamination of the EGR valve or metering flap.
- If you have problems starting, check the fuel pressure control valve in the rail.
- A low resource here is a generator, a thermostat, a boost pressure sensor.
- It should be borne in mind that for many works it is necessary to lower the motor along with the subframe.
