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.
1st gen Mercedes R4 family: M102, M111 E18, M111 E20, M111 E22, M111 E23, M166, M266, M271 E16, M271 E18.
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.
Frequently asked questions about the Mercedes M166
How much power does the Mercedes M166 make?
Power output of the Mercedes M166, hp: 82 (M 166 E 14); 82 - 102 (M 166 E 16); 125 (M 166 E 19); 140 (M 166 E 21). Torque, Nm: 130 (M 166 E 14); 140 - 150 (M 166 E 16); 180 (M 166 E 19); 205 (M 166 E 21).
How much oil does the Mercedes M166 take and which one?
Engine oil capacity: 4.5 liters. Recommended oil: 5W-40.
Does the Mercedes M166 have a timing belt or chain?
The Mercedes M166 uses a timing chain.
Is the Mercedes M166 turbocharged?
No, the Mercedes M166 is naturally aspirated.
Does the Mercedes M166 need valve clearance adjustment?
No, the Mercedes M166 has hydraulic lifters, so the valve clearances do not need to be adjusted.
How long does the Mercedes M166 last?
The typical lifespan of the Mercedes M166 is ~230 000 km with proper maintenance.
What is the fuel consumption of the Mercedes M166?
Mercedes A140 2001: city 9.7, highway 5.6, combined 7.1 L/100 km.
What cars was the Mercedes M166 installed on?
Mercedes A-Class W168 in 1997 - 2004; Mercedes Vaneo W414 in 2001 - 2005.
What are the common problems of the Mercedes M166?
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. All known problems.
