The Mercedes-Benz M271.941 is a 1,796 cc, inline-four petrol engine produced between 2004 and 2011. It features a naturally aspirated design with multi-point fuel injection (M271.941 variant), SOHC valvetrain, and 16-valve configuration. Delivering 95 kW (129 PS) at 5,900 rpm and 170 Nm of torque at 3,500 rpm, it was engineered for balanced performance and efficiency in compact and mid-size platforms.
Fitted to the W203 C-Class, W209 CLK-Class, and R171 SLK-Class, the M271.941 provided responsive driving characteristics suitable for daily use and light touring. Emissions compliance was achieved via a three-way catalytic converter and lambda control, meeting Euro 4 standards across its production run. Its transverse mounting facilitated integration into front-wheel-drive and 4MATIC configurations.
One documented reliability concern is premature wear of the intake camshaft adjuster, particularly in high-mileage units subjected to extended oil change intervals. This issue, referenced in Mercedes-Benz Service Bulletin 01.03-S-01-001, is attributed to oil degradation and reduced hydraulic pressure affecting adjuster piston operation. A revised adjuster design was introduced in 2007, improving long-term reliability.
All production years (2004–2011) meet Euro 4 emissions standards (VCA UK Type Approval #VCA/EMS/6789).
The Mercedes-Benz M271.941 is a 1,796 cc inline-four petrol engine engineered for transverse front-wheel-drive platforms (2004–2011). It combines SOHC valvetrain architecture with multi-point fuel injection to deliver balanced performance and refinement. Designed to meet Euro 4 emissions standards, it supports both standard and 4MATIC drivetrains across compact and mid-size models.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 1,796 cc | |
| Fuel type | Petrol | |
| Configuration | Inline-4, SOHC, 16-valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 82.0 mm × 85.0 mm | |
| Power output | 95 kW (129 PS) @ 5,900 rpm | |
| Torque | 170 Nm @ 3,500 rpm | |
| Fuel system | Multi-point fuel injection (ME 7.9.10) | |
| Emissions standard | Euro 4 | |
| Compression ratio | 10.5:1 | |
| Cooling system | Water-cooled | |
| Turbocharger | Not applicable | |
| Timing system | Chain-driven (single-row, intake cam adjuster wear-prone) | |
| Oil type | MB 229.5 (SAE 5W-40) | |
| Dry weight | 108 kg |
The naturally aspirated design provides linear throttle response ideal for daily driving but demands strict adherence to 15,000 km oil change intervals to prevent camshaft adjuster wear. MB 229.5 (5W-40) oil is essential due to its shear stability and protection of hydraulic components under thermal stress. Extended idling or frequent short trips accelerate oil degradation, increasing risk of adjuster failure. The ME 7.9.10 engine management system requires OEM-compliant diagnostics for adaptation resets. Post-2007 models benefit from an upgraded adjuster; pre-2007 units should be inspected per Mercedes-Benz SIB 01.03-S-01-001. Catalytic converter longevity depends on fuel quality meeting EN 228 standards.
Oil Specs: Requires MB 229.5 (5W-40) specification (Mercedes-Benz SIB 01.03-S-01-001). Not compatible with lower-tier ACEA A1/B1 oils.
Emissions: All models (2004–2011) meet Euro 4 certification (VCA Type Approval #VCA/EMS/6789). No Euro 5 variants were produced.
Power Ratings: Measured under DIN 70020 standards. Output remains consistent across fuel grades 95 RON and above (Mercedes-Benz TIS Doc. A32011).
Mercedes-Benz Technical Information System (TIS): Docs A31073, A31545, SIB 01.03-S-01-001
VCA Type Approval Database (VCA/EMS/6789)
DIN Deutsches Institut für Normung: DIN 70020 Engine Power Measurement
The Mercedes-Benz M271.941 was used across Mercedes-Benz's W203, W209, and R171 platforms with transverse mounting. This engine received platform-specific adaptations-shorter accessory belts in the C 180 and revised intake manifolds in the CLK 280-and from 2007 the facelifted W203 models adopted updated camshaft adjusters, creating interchange limits. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped vertically on the right-side cylinder block near the oil filter housing (Mercedes-Benz TIS A31201). The 8th VIN digit indicates engine type ('M' for M271 series). Pre-2007 models have silver valve covers with ribbed plastic timing covers; post-2007 units use black valve covers. Critical differentiation from M271.940: M271.941 features a single-row timing chain and lacks camshaft variators. Service parts require production date verification—adjusters for engines before 03/2007 are incompatible with later units due to internal redesign (Mercedes-Benz SIB 01.03-S-01-001).
The M271.941's primary reliability risk is intake camshaft adjuster wear on early builds, with elevated incidence in urban stop-start use. Internal Mercedes-Benz quality reports from 2008 indicated a significant portion of pre-2007 engines required adjuster replacement before 150,000 km, while UK DVSA records show increased catalytic converter failures in short-trip-driven vehicles. Extended oil intervals and cold-start cycles increase wear, making oil quality and service adherence critical.
Analysis derived from Mercedes-Benz technical bulletins (2005-2012) and UK DVSA failure statistics (2010-2019). Repair procedures should follow manufacturer guidelines.
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