Between 2004 and 2012, Mercedes M266 4-cylinder engines ranging in capacity from 1.5 to 2.0 liters were manufactured exclusively for the compact A-Class model and the comparable B-Class compact MPV. In essence, these power units were merely improved versions of the well-liked M166 engines.
M102, M111, M133, M139, M166, M200, M254, M260, M264, M266, M270, M271, M274, and M282 are the R4 Mercedes engines.
Specifications
| Production years | 2004-2012 |
| Displacement, cc | 1498 (M 266 E 15) 1699 (M 266 E 17) 2034 (M 266 E 20) |
| Fuel system | injector |
| Power output, hp | 95 (M 266 E 15) 116 (M 266 E 17) 136 (M 266 E 20) 193 (M 266 E 20 AL) |
| Torque output, Nm | 140 (M 266 E 15) 155 (M 266 E 17) 185 (M 266 E 20) 280 (M 266 E 20 AL) |
| Cylinder block | aluminum R4 |
| Block head | aluminum 8v |
| Cylinder bore, mm | 83 |
| Piston stroke, mm | 69.2 (M 266 E 15) 78.5 (M 266 E 17) 94 (M 266 E 20) |
| Compression ratio | 11.0 9.0 (M 266 E 20 AL) |
| Features | SOHC |
| Hydraulic lifters | yes |
| Timing drive | chain |
| Phase regulator | no |
| Turbocharging | no BorgWarner K03 (M 266 E 20 AL) |
| Recommended engine oil | 5W-30 |
| Engine oil capacity, liter | 5.0 |
| Fuel type | petrol |
| Euro standards | EURO 4/5 |
| Fuel consumption, L/100 km (for Mercedes A170 2008) — city — highway — combined |
10.2 5.4 7.2 |
| Engine lifespan, km | ~300 000 |
| Weight, kg | 90 |
The engine was installed on:
- Mercedes A-Class W169 in 2004 – 2012;
- Mercedes B-Class W245 in 2005 – 2011.
Disadvantages of the Mercedes M266 engine
This engine performs admirably in terms of dependability, but it cannot withstand poor fuel.
Here, the throttle assembly and nozzles quickly get dirty due to poor gasoline.
On specialized forums, there are numerous complaints regarding fuel pump failure and lubricant leaks.
The generator and air conditioning compressor clutch are two more areas where the motor is weak.
Many operations can only be performed by removing the engine because of the design features.