Only the original A-Class or a comparable Vaneo compact van were equipped with the 1.7-liter Mercedes OM668 or Vaneo 1.7 CDI engine, which was manufactured between 1998 and 2005. The standard DE 17 LA and the modified DE 17 LA red, which lacked an intercooler, were the two versions of the diesel engine.
OM616, OM601, OM604, OM611, OM640, OM646, OM651, OM654, and OM668 are members of the diesel R4-family.
The engine has a Common Rail fuel injection system, an intercooler, and a turbocharger. Two chain-driven overhead camshafts power the timing. A gearbox connects the first chain to the exhaust camshaft after it engages the intake camshaft. The oil pump is driven by a similar chain drive from the crankshaft. Cooling is accomplished by a transitional intercooler.
The camshaft and turbocharger of the OM668 series engines were altered in 2001. The rated power could be raised thanks to improvements. But the torque was unaffected because of the poor grip. By changing the electronic control unit’s software, the engine power can be raised to 118 horsepower. However, there won’t be any impact on the engine’s dependability or longevity.
Specifications
| Production years | 1998-2005 |
| Displacement, cc | 1689 |
| Fuel system | Common Rail |
| Power output, hp | 60 – 75 (Red) 90 – 95 |
| Torque output, Nm | 160 (Red) 180 |
| Cylinder block | aluminum R4 |
| Block head | aluminum 16v |
| Cylinder bore, mm | 80 |
| Piston stroke, mm | 84 |
| Compression ratio | 19.5 |
| Features | EGR (Red) EGR, intercooler |
| Hydraulic lifters | yes |
| Timing drive | chain |
| Phase regulator | no |
| Turbocharging | BorgWarner K03 |
| Recommended engine oil | 5W-30 |
| Engine oil capacity, liter | 4.5 |
| Fuel type | diesel |
| Euro standards | EURO 3 |
| Fuel consumption, L/100 km (for Mercedes Vaneo 2003) — city — highway — combined |
7.4 5.1 5.9 |
| Engine lifespan, km | ~250 000 |
| Weight, kg | 136 |
The OM668 was manufactured with a single displacement of 1689 cc, but it had four power options and three modifications:
- Since 2001, the Mercedes Benz A160 CDI has been equipped with version 668.940 (OM 668 DE 17 LA Red), which has 75 horsepower at 3700 rpm. “Red” denotes less power.
- Up until 2001, Mercedes Benz A170 CDI was equipped with version 668.940 (OM 668 DE 17 LA), which produced 90 horsepower at 4200 rpm.
- Up until 2001, the Mercedes Benz A160 CDI was equipped with version 668.941 (OM 668 DE 17 A), which had 60 horsepower at 3600 rpm. The lack of an intercooler made this change noteworthy.
- Since 2001, the Mercedes Benz A170 CDI has been equipped with version 668.942 (OM 668 DE 17 LA), which has 95 horsepower at 4200 rpm.
The engine was installed on:
- Mercedes A-Class W168 in 1998 – 2004;
- Mercedes Vaneo W414 in 2001 – 2005.
Disadvantages of the OM668 engine
There isn’t much room under the hood, and a subframe is needed to lower the diesel engine for maintenance.
The Bosch fuel system is dependable; frequently, only the fuel pressure regulator malfunctions.
Check the pressure sensor in the intake manifold and its pipe if there is a thrust loss.
Oil leaks through the heat exchanger or fuel leaks through the injection pump occur frequently.
This unit’s flow meter, generator, and EGR valve are also weak points.
Although the turbine is not weak, it frequently needs to be repaired after 200,000 kilometers.
Piston rings frequently lie and lubricant consumption appears after 200,000 kilometers.