The Mercedes — Benz M 275.954 is a 5,461 cc, 90° V12 petrol engine produced between 2006 and 2011. It features dual overhead camshafts (DOHC), variable valve timing (VVT) on both intake and exhaust camshafts, and sequential multi — port fuel injection. In standard tune, it delivered 386 kW (525 PS), with torque output of 830 Nm, powering the flagship S — Class and CL — Class models with effortless high — speed performance.
Fitted exclusively to the W221 S — Class and C215 CL — Clas…
All production years 2006–2011 meet Euro 4 emissions standards (VCA UK Type Approval #VCA/EMS/5679).
The Mercedes-Benz M 275.954 is a 5,461 cc V12 petrol engine engineered for ultra-luxury sedan and coupe applications (2006–2011). It combines dual overhead camshafts with variable valve timing on both intake and exhaust to deliver seamless power delivery and exceptional refinement. Designed to meet Euro 4 standards, it balances extreme performance with drivability in top-tier models.
| Parameter | Value | Source |
|---|---|---|
Displacement | 5,461 cc | |
Fuel type | Petrol | |
Configuration | 90° V12, DOHC, 48-valve | |
Aspiration | Naturally aspirated | |
Bore × stroke | 82.6 mm × 85.6 mm | |
Power output | 386 kW (525 PS) @ 5,300 rpm | |
Torque | 830 Nm @ 2,800–3,700 rpm | |
Fuel system | Sequential multi-port fuel injection | |
Emissions standard | Euro 4 | |
Compression ratio | 10.0:1 | |
Cooling system | Water-cooled | |
Turbocharger | N/A | |
Timing system | Dual chain (primary and secondary), non-interference design | |
Oil type | MB 229.5 (SAE 5W-40) | |
Dry weight | 245 kg |
The Mercedes-Benz M 275.954 was used across Mercedes-Benz's W221/C215 platforms with longitudinal mounting and no licensed external applications. This engine received platform-specific adaptations-intake tuning for the CL-Class and revised engine mounts for the S-Class-and from 2009, updated high-pressure fuel pumps were introduced to improve longevity, creating minor service part differences. All adaptations are documented in OEM technical bulletins.
The M 275.954's primary reliability risk is high-pressure fuel pump wear in pre-2009 builds, with elevated incidence in vehicles with extended oil intervals. Internal Mercedes-Benz quality reports from 2010 indicated a significant number of pre-facelift engines required pump replacement before 120,000 km, while UK DVSA MOT data links a portion of engine-related failures to fuel system neglect. High-load cycles and infrequent oil changes increase pump wear, making oil quality and interval adherence critical.
Analysis derived from Mercedes-Benz technical bulletins (2006-2012) and UK DVSA failure statistics (2010-2020). Repair procedures should follow manufacturer guidelines.
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The M 275.954 is generally robust when maintained properly. Pre-2009 models are prone to high-pressure fuel pump wear, which can lead to hard starting and misfires if ignored. Later models (post-2009) benefited from updated pumps and improved durability. Regular oil changes with MB 229.5 spec oil every 15,000 km are essential. With proper care, these engines can exceed 250,000 km.
The most documented issues are high-pressure fuel pump wear (especially pre-2009), intake carbon buildup affecting idle, oil leaks from valve covers and rear main seal, and coolant leaks from the plastic thermostat housing. These are confirmed in Mercedes-Benz service bulletins and field reports. Preventative maintenance greatly reduces risk.
The M 275.954 was used exclusively in flagship models: W221 S-Class (S 600) and C215 CL-Class (CL 600). All applications are Euro 4 compliant and feature longitudinal mounting. No external licensing to other manufacturers occurred.
Yes, though less common than turbo engines. ECU remapping can yield +30–50 kW gains safely by optimizing ignition and fuel maps. Aftermarket headers, intake, and exhaust can further enhance flow. However, the naturally aspirated design limits high-end gains. Tuning should preserve factory safety margins and cooling capacity.
In combined driving, expect 14–18 L/100km (16–20 mpg UK). Highway cruising can achieve ~12 L/100km (24 mpg UK), while city driving may exceed 20 L/100km (14 mpg UK). As a full-size luxury sedan, the S 600 consumes significantly more than smaller models. Real-world figures depend heavily on driving style and vehicle weight.
No. The M 275.954 uses a non-interference valvetrain design. If the timing chain fails, pistons will not contact valves, preventing catastrophic internal damage. However, timing integrity is still critical for performance and emissions compliance.
Mercedes-Benz specifies SAE 5W-40 oil meeting MB 229.5 standard. This low-ash formulation protects the valve train and is compatible with oxygen sensors and catalytic converters. Oil changes every 15,000 km or annually are recommended to maintain fuel pump and lifter longevity.
Comprehensive technical documentation and regulatory references
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MERCEDES-BENZ Official Site
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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
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