The Mercedes-Benz M271.957 is a 1,796 cc, inline-four petrol engine produced between 2008 and 2015. It features turbocharging, direct fuel injection (CGI), and variable valve timing (CAMTRONIC), delivering responsive performance and improved fuel efficiency. In standard tune it produced 115 kW (156 PS), with higher-output versions reaching 135 kW (184 PS) and torque outputs between 230–270 Nm, making it ideal for compact and mid-size platforms.
Fitted to models such as the W169 A-Class, W245 B-Class, and CL203 C-Class SportCoupe, the M271.957 was engineered for balanced urban and highway driving, offering strong low-end torque and smooth refinement. Emissions compliance was achieved through a three-way catalytic converter and lambda control, allowing Euro 5 certification across its production run. The engine's transverse layout enabled use in front-wheel-drive architectures, with shared components under platform agreements.
One documented concern is high-pressure fuel pump (HPFP) failure, particularly in early-build units subjected to extended oil change intervals or low-octane fuel. This issue, highlighted in Mercedes-Benz Service Information Bulletin 203070/13, stems from roller follower wear in the camshaft-driven pump. From 2012, revised HPFP hardware and updated cam lobe coatings were introduced to improve durability and reduce field failures.
All production years (2008–2015) meet Euro 5 emissions standards (VCA UK Type Approval #VCA/EMS/5679).
The Mercedes-Benz M271.957 is a 1,796 cc inline-four turbo petrol engine engineered for compact front-wheel-drive models (2008–2015). It combines turbocharging with CGI direct injection to deliver strong low-RPM torque and linear power delivery. Designed to meet Euro 5 standards, it balances performance with emissions efficiency and packaging constraints.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 1,796 cc | |
| Fuel type | Petrol | |
| Configuration | Inline-4, DOHC, 16-valve with CAMTRONIC | |
| Aspiration | Turbocharged | |
| Bore × stroke | 82.0 mm × 85.0 mm | |
| Power output | 115–135 kW (156–184 PS) | |
| Torque | 230–270 Nm @ 1,800–4,000 rpm | |
| Fuel system | CGI direct injection (up to 140 bar) | |
| Emissions standard | Euro 5 | |
| Compression ratio | 9.3:1 | |
| Cooling system | Water-cooled, electric coolant pump | |
| Turbocharger | Single turbo (BorgWarner) | |
| Timing system | Dual chain (lower and upper), non-interference design | |
| Oil type | MB 229.51 (SAE 5W-30) | |
| Dry weight | 128 kg |
The turbocharged design provides strong low-RPM torque ideal for city driving but requires strict adherence to 15,000 km oil change intervals using MB 229.51 oil to prevent HPFP and turbo wear. The CGI fuel system is sensitive to fuel quality; use of premium unleaded (RON 98) is recommended to minimise injector coking and carbon buildup. Extended idling after high-load operation should be avoided to reduce heat soak in the turbo and exhaust manifold. Post-2012 models feature updated HPFP components with improved cam lobe durability; pre-2012 units benefit from proactive replacement or inspection. The non-interference valvetrain reduces risk of catastrophic damage in the event of timing chain failure, though regular inspection is still advised.
Oil Specs: Requires MB 229.51 specification (Mercedes-Benz SIB 203070/13). Formulated for direct-injection turbo engines with low-SAPS requirements.
Emissions: Euro 5 certification applies to all model years (2008–2015) (VCA Type Approval #VCA/EMS/5679).
Power Ratings: Measured under ECE R85 standards. 135 kW output requires premium fuel (RON 98) and full engine warm-up (Mercedes-Benz TIS Doc. 640.00-E-110600).
Mercedes-Benz Technical Information System (TIS): Docs 640.00-E-110100, 640.00-E-110300, SIB 203070/13
VCA Type Approval Database (VCA/EMS/5679)
ISO 1585:1996 Road vehicles — Test method for fuel consumption in urban traffic
The Mercedes-Benz M271.957 was used across Mercedes-Benz's W169/W245/CL203 platforms with transverse mounting and shared with Chrysler under platform partnership agreements. This engine received platform-specific adaptations-shorter intake manifolds in the A-Class and revised cooling in the B-Class-and from 2012 the facelifted A-Class W169 LCI adopted the M271DE18 with updated HPFP hardware, creating interchange limits. Partnerships allowed Chrysler's 2.0L turbo units to share CGI injection technology. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped horizontally on the front of the cylinder block near the timing cover (Mercedes-Benz TIS 640.00-E-110900). The 7th VIN digit indicates engine family ('M' for M271 series). Pre-2012 models have silver valve covers with ribbed finish; post-2012 units use gloss black. Critical differentiation from M271DE18: Original M271.957 uses Bosch MED 17.8.8 ECU with 120-pin connector, while M271DE18 uses MED 17.8.21 with 144-pin. Service parts require production date verification - HPFP units for pre-2012 models are incompatible with later units due to internal cam follower redesign (Mercedes-Benz SIB 203070/13).
The M271.957's primary reliability risk is high-pressure fuel pump failure on early builds, with elevated incidence in urban driving with frequent short trips. Internal Mercedes quality reports from 2013 indicated a notable share of pre-2012 engines requiring HPFP replacement before 120,000 km, while UK DVSA records show increased catalyst failures linked to lean fuel trim events in poorly maintained units. Short-trip operation and delayed oil changes increase thermal stress, making oil quality and interval adherence critical.
Analysis derived from Mercedes-Benz technical bulletins (2012-2015) and UK DVSA failure statistics (2015-2023). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about MERCEDES-BENZ M271957.
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