2006 MERCEDES-BENZ C-Class M271 E18 (1.8L I4 Kompressor)/M112 E26 (2.6L V6, North America, some European markets) (W203)

Engine identity

Oils and fluids

Service and parts data

Common and chronic problems

• Timing chain wear on some early M271 engines
• Balance shaft bearing wear (M271)
• Water pump and thermostat failures
• Electrical issues in W203 body electronics

First checks

• Verify engine code and production month due to variation in specs
• Inspect timing chain and balance shaft condition on Kompressor engines
• Check for typical electrical gremlins (e.g., window regulators)
• Inspect suspension bushings and mounts for wear

Before replacing parts

• Save fault codes and freeze-frame data before clearing anything.
• Check engine oil, coolant and transmission fluid using the correct temperature and service procedure.
• Verify power, ground, connectors, hoses, leaks and live data before replacing expensive parts.

Important notes

• W203 chassis C-Class received a mid-cycle facelift in late 2004 with continued production until 2007; 2006 models mainly reflect this facelifted design.
• Technical specifications can vary significantly by market due to emission regulations and trim levels.
• Diesel engines primarily offered in Europe and select global markets; North America mostly petrol engines.