The 1.7-liter Mercedes OM668 or Vaneo 1.7 CDI engine was produced from 1998 to 2005 and was installed only on the first generation A-Class or a similar Vaneo compact van. The diesel engine had two versions: the regular DE 17 LA and the derated DE 17 LA red. without intercooler.
The diesel R4-family includes: OM616, OM601, OM604, OM611, OM640, OM646, OM651, OM654, OM668.
The engine is equipped with a turbocharger, a Common Rail fuel injection system and an intercooler. The timing is driven by 2 chain-driven overhead camshafts. The first chain engages the intake camshaft, and is connected to the exhaust camshaft by means of a gearbox. A similar chain drive from the crankshaft drives the oil pump. A transitional intercooler is responsible for cooling.
In 2001, the OM668 series engines underwent changes – the camshaft and turbocharger were modified. Improvements made it possible to increase the rated power. However, due to the weak grip, the torque remained untouched. The engine power can be increased to 118 hp. by reprogramming the software of the electronic control unit. At the same time, the reliability and durability of the engine will not be affected in any way.
|Fuel system||Common Rail|
|Power output, hp||60 – 75 (Red)
90 – 95
|Torque output, Nm||160 (Red)
|Cylinder block||aluminum R4|
|Block head||aluminum 16v|
|Cylinder bore, mm||80|
|Piston stroke, mm||84|
|Recommended engine oil||5W-30|
|Engine oil capacity, liter||4.5|
|Euro standards||EURO 3|
|Fuel consumption, L/100 km (for Mercedes Vaneo 2003)
|Engine lifespan, km||~250 000|
OM668 was produced with one single displacement – 1689 cc, but had three modifications and four power options:
- Version 668.940 (OM 668 DE 17 LA Red) with 75 hp at 3700 rpm, was installed on the Mercedes Benz A160 CDI since 2001. “Red” means reduced power.
- Version 668.940 (OM 668 DE 17 LA) with 90 hp at 4200 rpm and was installed on Mercedes Benz A170 CDI until 2001.
- Version 668.941 (OM 668 DE 17 A) with 60 hp at 3600 rpm, was installed on the Mercedes Benz A160 CDI until 2001. This modification was notable for the absence of an intercooler.
- Version 668.942 (OM 668 DE 17 LA) with 95 hp at 4200 rpm, was installed on the Mercedes Benz A170 CDI since 2001.
The engine was installed on:
- Mercedes A-Class W168 in 1998 – 2004;
- Mercedes Vaneo W414 in 2001 – 2005.
Disadvantages of the OM668 engine
- There is little space under the hood and for servicing the diesel engine must be lowered with a subframe.
- The Bosch fuel system is reliable, often only the fuel pressure regulator fails.
- If there is a loss of thrust, check the pressure sensor in the intake manifold and its pipe.
- Regularly there are fuel leaks through the injection pump or oil through the heat exchanger.
- The weak points of this unit also include a flow meter, a generator and an EGR valve.
- The turbine cannot be called weak, but it often requires repair by 200,000 km.
- After 200,000 km, piston rings often lie and lubricant consumption appears.