The Mercedes — Benz M 271.861 is a 1,796 cc, inline — four petrol engine produced between 2004 and 2012. It features naturally aspirated and supercharged variants, with twin overhead camshafts (DOHC), 16 — valve design, and variable valve timing (VVT) on both intake and exhaust camshafts. In supercharged form, it delivers up to 163 kW (221 PS) and 270 Nm of torque, powering performance — oriented compact models.
Fitted primarily to the C — Class (W203, W204), CLK — Class (C209…
Production years 2004–2009 meet Euro 4 standards; 2010–2012 models comply with Euro 5 depending on market .
The Mercedes-Benz M 271.861 is a 1,796 cc inline-four petrol engine engineered for compact and grand tourer applications (2004–2012). It combines naturally aspirated efficiency with Kompressor supercharging to deliver linear power delivery and strong mid-range response. Designed to meet Euro 4 and later Euro 5 emissions standards, it balances sporty performance with drivability.
| Parameter | Value | Source |
|---|---|---|
Displacement | 1,796 cc | |
Fuel type | Petrol | |
Configuration | Inline-4, DOHC, 16-valve | |
Aspiration | Naturally aspirated / Supercharged (Kompressor) | |
Bore × stroke | 82.0 mm × 85.0 mm | |
Power output | 125–163 kW (170–221 PS) | |
Torque | 240–270 Nm @ 3,000–4,600 rpm | |
Fuel system | Sequential multi-port fuel injection (ME 2.8/ME 7.8 ECU) | |
Emissions standard | Euro 4 (pre-2010); Euro 5 (2010–2012) | |
Compression ratio | 9.8:1 | |
Cooling system | Water-cooled | |
Turbocharger | Not applicable | |
Timing system | Chain-driven (double-row, wear-resistant) | |
Oil type | Refer to vehicle handbook / manufacturer specification | |
Dry weight | 138 kg |
The Mercedes-Benz M 271.861 was used across Mercedes-Benz's W203/W204/R171 platforms with longitudinal mounting. This engine received platform-specific adaptations-tuned intake manifolds in the C-Class and revised exhaust routing in the SLK-and from 2008 the facelifted W204 models adopted updated ECU mapping and actuator revisions, creating interchange limits. All adaptations are documented in OEM technical bulletins.
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Field reports and technical service bulletins highlight component wear patterns under high-load operation. Adherence to manufacturer service intervals and approved fluid specifications is critical for long-term reliability.
Analysis derived from manufacturer technical service bulletins and industry workshop records. Repair procedures should follow manufacturer guidelines.
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The M 271.861 is generally robust, but Kompressor variants (2004-2008) have known actuator reliability issues. Later revisions (post-2008) improved component durability. When maintained with regular oil changes (MB 229.5 spec) and coolant service, these engines can exceed 200,000 km. The chain-driven timing system is durable, and major internal failures are rare in well-serviced units.
The most documented issues are supercharger bypass actuator failure in Kompressor models, intake manifold flap malfunction, cooling system leaks (water pump/thermostat), and ignition coil degradation. These are covered in Mercedes-Benz service bulletins. Oil leaks from valve cover gaskets are also common on high-mileage engines.
This 1.8L petrol engine was used in several Mercedes-Benz models: C-Class (W203/W204), CLK-Class (C209), and SLK-Class (R171). It powered C 200 Kompressor, C 230, CLK 200 Kompressor, and SLK 200 Kompressor variants between 2004 and 2012. Both naturally aspirated and supercharged versions were offered depending on model year and trim.
Aftermarket ECU tuning is common on the M271861 platform, but increasing boost or altering engine parameters accelerates component wear, impacts emissions compliance, and may void vehicle warranties. Any modifications should be evaluated carefully by a qualified specialist.
In a C 200 Kompressor (W204), typical consumption is ~10.5 L/100km (city) and ~6.2 L/100km (highway), or about 37 mpg UK combined. Naturally aspirated C 230 models achieve slightly better economy (~9.0 L/100km combined). Real-world figures depend on driving style, but expect 30-40 mpg (UK) on mixed roads for Kompressor models.
Yes. The M 271 series is an interference engine. If the timing chain fails or jumps, pistons can collide with open valves, causing catastrophic engine damage. While the chain is durable, any unusual noise from the front of the engine should be investigated immediately to prevent costly repairs.
Mercedes-Benz specifies SAE 5W-40 oil meeting MB 229.5 standard. This full-synthetic oil is essential for protecting the supercharger bearings and timing chain under high thermal loads. Change intervals should not exceed 15,000 km or one year, whichever comes first, to ensure long-term reliability.
Comprehensive technical documentation and regulatory references
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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
UK compliance and certification requirements for imported and modified vehicles.
VCA Certification Portal
Type-approval guidance and documentation.
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