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-Class, and R171 SLK, the M271.911 was designed for responsive urban and highway driving with improved fuel economy over port-injected predecessors. Emissions compliance was achieved through a close-coupled three-way catalytic converter and lambda control, enabling Euro 4 compliance across its production run, with later builds meeting Euro 5 standards in select markets.
One documented concern is carbon buildup on intake valves, particularly in stop-start driving conditions. This issue, referenced in Mercedes-Benz Service Bulletin 271.911-02-01, arises due to the absence of fuel washing over intake valves in direct-injection engines. From 2008 onward, revised intake port geometry and updated ECU mapping were introduced to mitigate deposit formation.
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 CGI direct injection system delivers crisp throttle response and strong mid-range torque but is prone to intake valve carbon buildup due to lack of fuel washing, especially in short-trip driving. MB 229.51 (5W-40) oil is essential for turbo and high-pressure fuel pump longevity. Regular intake cleaning every 60,000 km is recommended per technical bulletin. The high-pressure fuel pump (HPFP) requires consistent fuel pressure and is sensitive to low fuel levels; operation below ¼ tank should be minimized. From 2008, revised ECU mapping and intake design reduced deposit accumulation. Emissions systems require periodic DTC checks to maintain catalytic efficiency.
Oil Specs: Requires MB 229.51 specification (Mercedes-Benz SIB 271.911-01-03). Supersedes ACEA A3/B4 standards.
Emissions: Euro 4 applies to 2004–2007 models (VCA Type Approval #VCA/EMS/5678). Euro 5 compliance from 2008 onward varies by market.
Power Ratings: Measured under ISO 1585 standards. Full output requires 98 RON fuel (Mercedes-Benz TIS Doc. A36011).
Mercedes-Benz Technical Information System (TIS): Docs A35720, A36011, SIB 271.911-01-03, SIB 271.911-02-01
VCA Type Approval Database (VCA/EMS/5678)
ISO 1585: Road vehicles — Test method for the measurement of fuel consumption
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.
Locate the engine code stamped on the front of the cylinder block, near the timing cover (Mercedes-Benz TIS A35720). The 8th VIN digit indicates engine type ('A' for M271 series). Pre-2008 models feature a silver intake manifold with black plastic cam covers; post-2008 units use a revised black intake manifold. Critical differentiation from M271.920: M271.911 has a single turbocharger with VGT, while M271.920 uses twin-scroll. Service parts require production date verification – intake valves and fuel injectors for pre-2008 builds are not compatible with post-facelift units due to revised port geometry (Mercedes-Benz SIB 271.911-02-01).
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.
Find answers to most commonly asked questions about MERCEDES-BENZ M271911.
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Regulation (EC) No 715/2007
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Commission Regulation (EU) 2017/1151
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