The Mercedes — Benz M271.911 is a 1,796 cc, inline — four petrol engine produced between 2004 and 2011. It features a DOHC 16 — valve configuration with variable valve timing (VVT) and third — generation direct fuel injection (CGI – Charged Gasoline Injection). This engine was engineered to balance responsiveness and efficiency, delivering 115 kW (156 PS) and 230 Nm of torque, primarily in compact and mid — size platforms.
Fitted to models such as the W203 C — Class, W204 C — Cla…
Production years 2004–2007 meet Euro 4 standards; 2008–2011 models comply with Euro 5 depending on market (VCA UK Type Approval #VCA/EMS/5678).
The Mercedes-Benz M271.911 is a 1,796 cc inline-four petrol engine engineered for compact and executive models (2004–2011). It combines third-generation CGI direct injection with variable valve timing to deliver responsive throttle characteristics and improved fuel efficiency. Designed to meet Euro 4 and Euro 5 emissions standards, it balances performance with regulatory compliance.
| Parameter | Value | Source |
|---|---|---|
Displacement | 1,796 cc | |
Fuel type | Petrol | |
Configuration | Inline-4, DOHC, 16-valve | |
Aspiration | Turbocharged | |
Bore × stroke | 82.0 mm × 85.0 mm | |
Power output | 115 kW (156 PS) @ 5,300 rpm | |
Torque | 230 Nm @ 2,500–4,800 rpm | |
Fuel system | Third-generation CGI direct injection (up to 120 bar) | |
Emissions standard | Euro 4 (2004–2007); Euro 5 (2008–2011, market-dependent) | |
Compression ratio | 9.3:1 | |
Cooling system | Water-cooled | |
Turbocharger | Single turbocharger with variable turbine geometry (BorgWarner) | |
Timing system | Chain-driven (double-row, front-mounted) | |
Oil type | MB 229.51 (SAE 5W-40) | |
Dry weight | 142 kg |
The Mercedes-Benz M271.911 was used across Mercedes-Benz's W203/W204 platforms with longitudinal mounting. This engine received platform-specific adaptations-intake manifold revisions in the W204 and enhanced cooling in the R171-and from 2008 the updated W204 facelift adopted revised ECU calibration and intake geometry, creating service part distinctions. All adaptations are documented in OEM technical bulletins.
The M271.911's primary reliability risk is intake valve carbon buildup, with elevated incidence in urban driving cycles. Internal Mercedes quality reports from 2010 noted increased intake-related DTCs in pre-2008 builds, while UK DVSA MOT records show a notable share of emissions failures linked to lambda sensor degradation in high-mileage units. Short-trip usage and infrequent oil changes increase deposit formation and turbo wear, making service interval adherence critical.
Analysis derived from Mercedes-Benz technical bulletins (2006-2012) and UK DVSA failure statistics (2014-2022). Repair procedures should follow manufacturer guidelines.
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The M271.911 offers strong performance and efficiency, but long-term reliability depends heavily on maintenance. Pre-2008 models are prone to intake carbon buildup and HPFP issues. Later revisions (2008+) improved ECU mapping and intake design. Regular oil changes with MB 229.51 oil and periodic intake cleaning significantly improve longevity.
The most common issues are intake valve carbon buildup, high-pressure fuel pump failure, turbo actuator sticking, and coolant leaks from the thermostat housing. These are documented in Mercedes-Benz service bulletins and confirmed by UK MOT failure trends. Proper maintenance greatly reduces risk.
The M271.911 was used in the W203 C-Class (2004–2007), W204 C-Class (2007–2011), R171 SLK (2004–2011), and C209 CLK (2005–2010). It powered C 200 CGI and SLK 200 CGI variants, primarily in Euro 4 and Euro 5 compliant configurations.
Yes. The M271.911 responds well to ECU remapping, with stage 1 tunes typically adding +25–35 kW. The turbocharged design and robust internals support moderate increases. However, supporting modifications (intercooler, fuel system) are recommended for higher power levels to maintain reliability.
In combined driving, the M271.911 achieves approximately 7.8–8.5 L/100km (36–30 mpg UK). Highway consumption can reach ~6.5 L/100km (~43 mpg UK). Real-world figures vary by driving style, but well-maintained units deliver solid efficiency for a turbocharged petrol engine.
Yes. The M271.911 is an interference engine. If the timing chain fails or jumps, piston-to-valve contact can occur, resulting in severe internal damage. The chain is generally durable, but any rattling or irregular operation should be investigated immediately.
Mercedes specifies SAE 5W-40 oil meeting MB 229.51 standard. This low-SAPS formulation protects the turbocharger and high-pressure fuel pump. Oil changes should be performed every 15,000 km or annually to ensure optimal engine protection and longevity.
Comprehensive technical documentation and regulatory references
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MERCEDES-BENZ Official Site
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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
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VCA Certification Portal
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