The Mercedes — Benz M271.946 is a 1,796 cc, inline — four petrol engine produced between 2008 and 2015. It features a DOHC 16 — valve configuration with variable valve timing (VVT) and direct fuel injection, delivering 135 kW (184 PS) and 270 Nm of torque. This evolution of the M271 series introduced spray — guided direct injection for improved efficiency and responsiveness, particularly in urban driving conditions.
Fitted to models such as the W204 C — Class, W245 B — Class, a…
All production years (2008–2015) meet Euro 5 emissions standards (VCA UK Type Approval #VCA/EMS/5679).
The Mercedes-Benz M271.946 is a 1,796 cc inline-four petrol engine engineered for compact and mid-size platforms (2008–2015). It combines spray-guided direct fuel injection with variable valve timing to deliver strong mid-range torque and responsive urban performance. Designed to meet Euro 5 standards, it balances performance with regulated emissions control and improved fuel stratification.
| Parameter | Value | Source |
|---|---|---|
Displacement | 1,796 cc | |
Fuel type | Petrol | |
Configuration | Inline-4, DOHC, 16-valve | |
Aspiration | Naturally aspirated | |
Bore × stroke | 82.0 mm × 85.0 mm | |
Power output | 135 kW (184 PS) @ 5,500 rpm | |
Torque | 270 Nm @ 3,000–4,600 rpm | |
Fuel system | Spray-guided direct injection (ME 9.7 ECU) | |
Emissions standard | Euro 5 | |
Compression ratio | 10.7:1 | |
Cooling system | Water-cooled | |
Turbocharger | Not applicable | |
Timing system | Chain-driven (double-row, non-interference) | |
Oil type | MB 229.51 (SAE 5W-30) | |
Dry weight | 146 kg |
The Mercedes-Benz M271.946 was used across Mercedes-Benz's W204/CL203 platforms with longitudinal mounting and adapted for transverse applications in the W245 B-Class. This engine received platform-specific adaptations-shorter intake manifolds in the W245 and revised engine mounts in the W204-and from 2012 the updated W204 facelift adopted revised intake runners and ECU mapping, creating service part interchange limits. All adaptations are documented in OEM technical bulletins.
The M271.946's primary reliability risk is intake valve carbon buildup, with elevated incidence in urban driving and short-trip usage. Internal Mercedes-Benz quality reports from 2013 indicated a significant portion of pre-2012 engines required intake cleaning before 100,000 km, while UK DVSA records show a notable share of emissions-related MOT failures linked to misfires from clogged ports. Frequent cold starts and low-RPM operation increase deposit formation, making maintenance intervals and fuel quality critical.
Analysis derived from Mercedes-Benz technical bulletins (2010–2014) and UK DVSA failure statistics (2015–2023). Repair procedures should follow manufacturer guidelines.
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The M271.946 offers responsive performance and improved efficiency over earlier M271 variants, but is prone to intake valve carbon buildup, especially in city driving. Well-maintained engines with regular intake cleaning, use of MB 229.51 oil, and adherence to 15,000 km service intervals can reliably exceed 180,000 km. Post-2012 models benefit from revised intake designs that reduce deposit accumulation.
Primary issues include intake valve carbon buildup (due to direct injection), high-pressure fuel pump failure, throttle body faults causing limp mode, and ignition coil failures. These are documented in Mercedes-Benz service bulletins and verified through technical workshops and DVSA data. Carbon cleaning and fuel system maintenance are critical for long-term reliability.
This 1.8L petrol engine was used in the W204 C-Class (C 200 CGI), CL203 C-Class Coupe (C 200 CGI), W245 B-Class (B 200 CGI), and X204 GLK-Class (GLK 200 CGI). It was produced from 2008 to 2015 and replaced by turbocharged M270/M274 engines. All variants meet Euro 5 emissions standards.
Limited potential. As a naturally aspirated direct-injection engine, ECU remapping yields modest gains (typically +10–15 kW). Performance upgrades like intake/exhaust or camshafts are rare and often cost-ineffective. The design prioritizes refinement and efficiency over tunability, so modifications are generally not recommended.
Moderate. In a W204 C 200 CGI (2010), combined consumption is ~8.2 L/100km (~34 mpg UK). City driving may see 9–11 L/100km, while highway runs can achieve 6.8–7.5 L/100km. Real-world figures depend on driving style, but expect 30–36 mpg UK on mixed routes for a well-maintained unit.
No. The M271.946 uses a non-interference timing chain design. If the chain fails or jumps, the pistons will not contact the valves, preventing catastrophic internal damage. However, immediate repair is still required to avoid valve timing issues and drivability problems.
Mercedes-Benz specifies SAE 5W-30 oil meeting MB 229.51 standard. This synthetic oil is critical for protecting the high-pressure fuel pump and variable valve timing system. Change intervals should not exceed 15,000 km or 12 months to ensure long-term reliability and prevent carbon buildup.
Comprehensive technical documentation and regulatory references
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EU emissions and type-approval regulations (e.g., CELEX:32007R0715, CELEX:32017R1151).
GOV.UK: Vehicle Approval & V5C
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DVLA: Engine Changes & MoT
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Vehicle Certification Agency (VCA)
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Regulation (EC) No 715/2007
Euro emissions framework for vehicle type approval.
Commission Regulation (EU) 2017/1151
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