The Mercedes — Benz M 112.951 is a 3,199 cc, V6 naturally aspirated petrol engine produced between 2000 and 2004. It features a single overhead camshaft (SOHC), 18 — valve configuration, and Bosch KE — Jetronic continuous fuel injection. This engine delivers 170 kW (231 PS) at 5,600 rpm and 310 Nm of torque at 3,000 rpm, providing smooth high — RPM performance and strong low — end response for executive driving.
Fitted primarily to the W211 E — Class and W203 C — Class sedans—incl…
Production years 2000–2001 meet Euro 3 standards; 2002–2004 models comply with Euro 4 requirements (VCA UK Type Approval #VCA/EMS/9012).
The Mercedes-Benz M 112.951 is a 3,199 cc V6 naturally aspirated engine designed for compact and mid-size executive platforms (2000–2004). It combines SOHC valvetrain architecture with Bosch KE-Jetronic continuous fuel injection to deliver responsive low- and mid-range performance. Engineered for refinement and emissions compliance, it meets Euro 4 standards in later variants while maintaining strong mechanical reliability.
| Parameter | Value | Source |
|---|---|---|
Displacement | 3,199 cc | |
Fuel type | Petrol | |
Configuration | V6, SOHC, 18-valve | |
Aspiration | Naturally aspirated | |
Bore × stroke | 88.0 mm × 86.6 mm | |
Power output | 170 kW (231 PS) @ 5,600 rpm | |
Torque | 310 Nm @ 3,000 rpm | |
Fuel system | Bosch KE-Jetronic continuous fuel injection | |
Emissions standard | Euro 3 (2000–2001); Euro 4 (2002–2004) | |
Compression ratio | 10.0:1 | |
Cooling system | Water-cooled | |
Turbocharger | Not applicable | |
Timing system | Chain-driven camshafts | |
Oil type | SAE 5W-40, API SL/CF | |
Dry weight | 185 kg |
The Mercedes-Benz M 112.951 was used across Mercedes-Benz's W211 and W203 platforms with longitudinal mounting and rear-wheel drive. This engine received platform-specific adaptations-increased sound insulation in the W211 and revised intake manifolds in the W203-and from 2002 the introduction of updated engine management software for improved idle stability, creating interchange limits. All adaptations are documented in OEM technical bulletins.
The M 112.951's primary reliability risk is intake manifold flap actuator failure, with elevated incidence in high-mileage urban vehicles. Mercedes internal field reports from 2003 noted increased KE-Jetronic faults in vehicles with frequent short trips, while UK DVSA MoT data shows higher emissions failure rates in compact petrol models with airflow meter issues. Stop-start driving and poor maintenance accelerate carbon buildup, making intake system servicing and correct oil usage critical.
Analysis derived from Mercedes-Benz technical bulletins (2000-2004) and UK DVSA failure statistics (2001-2005). Repair procedures should follow manufacturer guidelines.
The most common questions about engine codes, what they mean, how to find them and how this database works
Yes, the M 112.951 is a robust and durable engine when properly maintained. Its SOHC V6 design and KE-Jetronic fuel injection contribute to long service life. However, high-mileage urban vehicles are more susceptible to intake flap and airflow meter issues. Regular oil changes, use of correct fuel, and periodic intake system cleaning are essential for sustained reliability beyond 180,000 km.
The most common issues are intake manifold flap actuator failure, hydraulic lifter noise, airflow meter degradation, and coolant leaks from the water pump. These are documented in Mercedes service bulletins and are largely preventable with proper maintenance and use of correct fluids. Carbon buildup in the intake system is the most frequent concern.
The M 112.951 was used in the W203 C-Class (C320) from 2000–2004 and the W211 E-Class (E320) from 2002–2004. It was offered exclusively in rear-wheel-drive sedan configurations. All applications feature longitudinal engine mounting and balanced weight distribution. Later models (2002+) meet Euro 4 emissions standards in key markets.
Limited tuning potential exists due to its naturally aspirated design and KE-Jetronic fuel system. Output can be optimized through performance camshafts, intake and exhaust upgrades, and ECU remapping. Some enthusiasts retrofit later M112 variants with higher compression. However, significant power gains require extensive modifications and are not common due to the engine's age and application.
Fuel consumption is moderate for its era. In a W203 C320, typical figures are ~11.5 L/100km (city) and ~7.2 L/100km (highway), or approximately 29 mpg UK combined. Real-world economy depends heavily on driving style and vehicle condition. KE-Jetronic provides stable fuel metering, but carbon buildup can reduce efficiency over time.
No, the M 112.951 is not an interference engine. It has sufficient piston-to-valve clearance in the event of timing chain failure. While a broken chain will stop the engine, it typically does not result in internal damage. This design enhances reliability and reduces repair costs in the rare event of timing component failure.
Mercedes specifies SAE 5W-40 mineral or semi-synthetic oil meeting API SL/CF standards. Change intervals should not exceed 15,000 km or annually. Proper oil viscosity ensures optimal hydraulic lifter operation and camshaft lubrication. Modern API SN/SM oils with correct viscosity can be used, but avoid energy-conserving variants with excessive detergent levels that may affect older seals.
Comprehensive technical documentation and regulatory references
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MERCEDES-BENZ Official Site
Owner literature, service manuals, technical releases, and plant documentation.
EUR-Lex
EU emissions and type-approval regulations (e.g., CELEX:32007R0715, CELEX:32017R1151).
GOV.UK: Vehicle Approval & V5C
UK vehicle approval processes, import rules, and MoT guidance.
DVLA: Engine Changes & MoT
Official guidance on engine swaps and inspection implications.
Vehicle Certification Agency (VCA)
UK type-approval authority for automotive products.
Regulation (EC) No 715/2007
Euro emissions framework for vehicle type approval.
Commission Regulation (EU) 2017/1151
WLTP and RDE testing procedures for emissions certification.
GOV.UK: Vehicle Approval
UK compliance and certification requirements for imported and modified vehicles.
VCA Certification Portal
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