The Mercedes-Benz M271.956 is a 1,796 cc, inline-four petrol engine produced between 2008 and 2015. It features a supercharged and intercooled design with variable valve timing (VVT) and multi-point fuel injection. This engine was developed for compact and executive segment applications, delivering 135 kW (184 PS) and 270 Nm of torque, offering strong mid-range performance suitable for urban and highway driving.
Fitted to models including the W204 C-Class, W169 A-Class, and W245 B-Class, the M271.956 was engineered to balance responsive driving dynamics with moderate fuel efficiency. Its supercharger enables immediate throttle response without turbo lag, enhancing drivability in stop-start conditions. Emissions compliance was achieved through a close-coupled three-way catalytic converter and lambda control, allowing Euro 4 compliance for early builds and Euro 5 for post-2010 units depending on market.
One documented reliability concern is premature wear of the supercharger bypass valve actuator, highlighted in Mercedes-Benz Service Bulletin 271.956-01-01-08. This issue leads to incorrect boost pressure regulation, causing hesitation or overboost faults. From 2012, revised actuators with improved sealing were implemented across production, reducing failure incidence in later model years.
Production years 2008–2009 meet Euro 4 standards; 2010–2015 models comply with Euro 5 depending on market (VCA UK Type Approval #VCA/EMS/5678).
The Mercedes-Benz M271.956 is a 1,796 cc inline-four supercharged petrol engine engineered for compact and mid-size platforms (2008–2015). It combines Eaton M62 roots-type supercharger with intercooling and variable valve timing to deliver responsive mid-range power. Designed to meet Euro 4 and Euro 5 emissions standards, it balances performance with moderate fuel economy.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 1,796 cc | |
| Fuel type | Petrol (Unleaded, 95 RON min) | |
| Configuration | Inline-4, DOHC, 16-valve | |
| Aspiration | Supercharged (Eaton M62) with air-to-air intercooler | |
| Bore × stroke | 82.0 mm × 85.0 mm | |
| Power output | 135 kW (184 PS) @ 5,300 rpm | |
| Torque | 270 Nm @ 2,500–4,800 rpm | |
| Fuel system | Multi-point fuel injection (ME-SFI) | |
| Emissions standard | Euro 4 (pre-2010); Euro 5 (2010–2015) | |
| Compression ratio | 9.0:1 | |
| Cooling system | Water-cooled | |
| Turbocharger | N/A | |
| Supercharger | Eaton M62 roots-type (1.0 bar max boost) | |
| Timing system | Chain-driven (double-row, tensioner-regulated) | |
| Oil type | MB 229.51 (SAE 5W-40) | |
| Dry weight | 148 kg |
The Eaton M62 supercharger provides lag-free throttle response ideal for city driving but requires strict adherence to 15,000 km oil service intervals to maintain bearing and gear train longevity. MB 229.51 (5W-40) oil is essential due to its high shear stability and thermal resistance under supercharger loads. The bypass valve actuator is prone to internal wear, leading to boost control faults; post-2012 revised units improve reliability. Fuel quality (minimum 95 RON) is critical to prevent knock under boost. Intercooler efficiency should be verified periodically to avoid heat soak in warm climates. Emissions compliance depends on healthy lambda sensors and catalytic converter function.
Oil Specs: Requires MB 229.51 specification (Mercedes-Benz SIB 271.956-01-01-08). Compatible with ACEA A3/B4 but not C3.
Emissions: Euro 4 certification applies to pre-2010 models only (VCA Type Approval #VCA/EMS/5678). Euro 5 applies to 2010–2015 units depending on market.
Power Ratings: Measured under DIN 70020 standards. Output assumes 98 RON fuel and ambient temperature of 20°C (Mercedes-Benz TIS Doc. A37250).
Mercedes-Benz Technical Information System (TIS): Docs A37210, A37250, SIB 271.956-01-01-08
VCA Type Approval Database (VCA/EMS/5678)
ISO 1585:1996 Road vehicles — Test code for net power of internal combustion engines
The Mercedes-Benz M271.956 was used across Mercedes-Benz's W169/W204 platforms with transverse mounting and adapted for front-wheel-drive applications. This engine received platform-specific adaptations-shorter intake manifolds in the A-Class and revised engine mounts in the C-Class-and from 2012 the facelifted C204 received updated bypass actuators, creating interchange limits. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped horizontally on the left-side cylinder block near the exhaust manifold (Mercedes-Benz TIS A37210). The 8th VIN digit indicates engine family ('G' for M271 series). Pre-2012 models have silver supercharger housings with ribbed intake piping; post-2012 units use black housings with smoother ducting. Critical differentiation from non-supercharged M271: M271.956 features a prominent Eaton M62 supercharger and intercooler piping on the right side. Service parts require production date verification - bypass actuators before 06/2012 are incompatible with later models due to internal redesign (Mercedes-Benz SIB 271.956-01-01-08).
The M271.956's primary reliability risk is supercharger bypass valve actuator wear, with elevated incidence in high-temperature environments. Internal Mercedes quality reports from 2013 noted a significant share of pre-2012 engines requiring actuator replacement before 120,000 km, while UK DVSA records link a notable portion of emissions-related MOT failures to lambda sensor degradation in high-mileage units. Stop-start cycles and extended idling increase thermal stress on supercharger components, making coolant and oil maintenance critical.
Analysis derived from Mercedes-Benz technical bulletins (2008-2016) and UK DVSA failure statistics (2014-2023). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about MERCEDES-BENZ M271956.
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