4-cylinder Mercedes M166 engines from 1.4 to 2.1 liters were produced from 1997 to 2005 and were installed only on the compact A-class model and the Vaneo compact van, created on its basis. After upgrading to the next generation A-class, these units changed their index to M266.
R4 Mercedes engines: M102, M111, M133, M139, M166, M200, M254, M260, M264, M266, M270, M271, M274, M282.
Specifications
| Production years | 1997-2005 |
| Displacement, cc | 1397 (M 166 E 14) 1598 (M 166 E 16) 1898 (M 166 E 19) 2084 (M 166 E 21) |
| Fuel system | injector |
| Power output, hp | 82 (M 166 E 14) 82 – 102 (M 166 E 16) 125 (M 166 E 19) 140 (M 166 E 21) |
| Torque output, Nm | 130 (M 166 E 14) 140 – 150 (M 166 E 16) 180 (M 166 E 19) 205 (M 166 E 21) |
| Cylinder block | aluminum R4 |
| Block head | aluminum 8v |
| Cylinder bore, mm | 80 (M 166 E 14) 80 (M 166 E 16) 84 (M 166 E 19) 84 (M 166 E 21) |
| Piston stroke, mm | 69.5 (M 166 E 14) 79.5 (M 166 E 16) 85.6 (M 166 E 19) 94 (M 166 E 21) |
| Compression ratio | 11.0 (M 166 E 14) 11.0 (M 166 E 16) 10.8 (M 166 E 19) 11.0 (M 166 E 21) |
| Features | SOHC |
| Hydraulic lifters | yes |
| Timing drive | chain |
| Phase regulator | no |
| Turbocharging | no |
| Recommended engine oil | 5W-40 |
| Engine oil capacity, liter | 4.5 |
| Fuel type | petrol |
| Euro standards | EURO 3/4 |
| Fuel consumption, L/100 km (for Mercedes A140 2001) — city — highway — combined |
9.7 5.6 7.1 |
| Engine lifespan, km | ~230 000 |
| Weight, kg | 95 |
The engine was installed on:
- Mercedes A-Class W168 in 1997 – 2004;
- Mercedes Vaneo W414 in 2001 – 2005.
Disadvantages of the Mercedes M166 engine
- The first years of production, the engines were equipped with an unreliable ECU with a built-in flow meter.
- Corrosion and rapid wear of the cams and camshaft journals are also common here.
- Due to cracked crankcase ventilation pipes, the smell of exhaust gases can be felt in the cabin.
- The timing chain, generator, water pump and oil pump are distinguished by a low resource.
- Due to the unusual design, many operations are carried out with the removal of the engine.
