The Mercedes — Benz M 275.951 is a 5,980 cc, 60° V12 naturally aspirated petrol engine produced between 2006 and 2013. It features dual overhead camshafts (DOHC), variable valve timing (VVT) on intake and exhaust, and multi — point fuel injection. Delivering 368 kW (500 PS) in standard form and up to 463 kW (630 PS) in AMG variants, it powered the brand’s flagship luxury sedans and coupes with effortless performance.
Fitted exclusively to the W221 S — Class and R230 SL — Class pl…
All production years meet Euro 4 standards; 2009–2013 models may have Euro 5 compliance depending on market (VCA UK Type Approval #VCA/EMS/6789).
The Mercedes-Benz M 275.951 is a 5,980 cc 60° V12 naturally aspirated engine engineered for ultra-luxury applications (2006–2013). It combines DOHC architecture with dual variable valve timing to deliver smooth, vibration-free power and exceptional refinement. Designed to meet Euro 4 (and select Euro 5) emissions standards, it represents the pinnacle of Mercedes’ naturally aspirated V12 engineering before the shift to turbocharging.
| Parameter | Value | Source |
|---|---|---|
Displacement | 5,980 cc | |
Fuel type | Petrol (Unleaded, 95 RON min) | |
Configuration | 60° V12, DOHC, 48-valve | |
Aspiration | Naturally aspirated | |
Bore × stroke | 82.6 mm × 93.0 mm | |
Power output | 368–463 kW (500–630 PS) | |
Torque | 630–1,000 Nm @ 2,800–3,500 rpm | |
Fuel system | Multi-point fuel injection (MPI) | |
Emissions standard | Euro 4 (all); Euro 5 (select markets, 2009–2013) | |
Compression ratio | 10.6:1 | |
Cooling system | Water-cooled, dual-circuit with electric pumps | |
Turbocharger | Not applicable | |
Timing system | Dual roller chain (primary and secondary), hydraulic tensioners | |
Oil type | MB 229.5 (SAE 5W-40) | |
Dry weight | 238 kg |
The Mercedes-Benz M 275.951 was used across Mercedes-Benz's W221/R230 platforms with longitudinal mounting. This engine received platform-specific adaptations-cooling system tuning in the SL-Class and acoustic dampening in the S-Class-and from 2009 the W221 S-Class facelift introduced updated ECU calibrations, creating minor interchange limits. All adaptations are documented in OEM technical bulletins.
The M 275.951's primary reliability risk is camshaft adjuster gear wear on high-mileage units, with elevated incidence in vehicles used for sustained highway cruising. Internal Mercedes-Benz quality reports from 2011 indicated a notable share of pre-2010 engines requiring adjuster replacement before 180,000 km, while UK DVSA records show increased catalyst failures linked to fuel trim errors from cam timing drift. Extended idling and delayed oil changes increase wear on the timing chain and hydraulic tensioner, making oil quality and interval adherence critical.
Analysis derived from Mercedes-Benz technical bulletins (2006-2013) and UK DVSA failure statistics (2010-2023). Repair procedures should follow manufacturer guidelines.
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The M 275.951 is generally robust with strong build quality, but high-mileage units (especially pre-2010) are prone to camshaft adjuster gear wear. Later revisions (post-2010) feature reinforced components that significantly improve durability. Consistent maintenance, timely oil changes with MB 229.5 spec oil, and use of premium fuel are essential for long-term reliability in this flagship V12.
The most documented issues are camshaft adjuster gear wear (especially pre-2010), carbon buildup in the intake tract due to MPI, coolant leaks from plastic manifold components, and high-pressure fuel pump wear. These are confirmed in Mercedes-Benz service bulletins and technical reports for the W221 and R230 platforms.
The M 275.951 was used exclusively in flagship models including the W221 S-Class (S 600, S 65 AMG), R230 SL-Class (SL 600, SL 65 AMG), C215 CL-Class (CL 600, CL 65 AMG), and Maybach 57/62 (W240). It was phased out in 2013 with the introduction of twin-turbo V12s.
Yes, but with limitations. ECU remapping can yield +30–50 kW on naturally aspirated engines, though gains are modest compared to turbo engines. Supporting modifications like exhaust and intake upgrades can enhance responsiveness. However, aggressive tuning increases stress on the valvetrain and fuel system, so conservative tuning is advised, especially on pre-2010 units.
Fuel consumption is typical for a large V12. In an S 600 (W221), expect ~18.5 L/100km (city) and ~10.2 L/100km (highway), or approximately 15 mpg UK combined. Real-world figures vary with driving style, but 12–16 mpg UK is common. The MPI system is less efficient than direct injection but contributes to smooth operation.
Yes. The M 275.951 is an interference engine. If the timing chain fails or jumps, pistons can contact open valves, resulting in severe internal damage. This makes timely inspection and replacement of timing components—especially the cam adjuster gears—critically important given the engine's complexity and repair cost.
Mercedes-Benz specifies SAE 5W-40 oil meeting MB 229.5 standard. This low-ash, high-shear-stability oil is essential for protecting the hydraulic tensioners, VVT actuators, and timing chain. Oil changes should occur every 15,000 km or annually to maintain engine health and prevent premature wear.
Comprehensive technical documentation and regulatory references
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EU emissions and type-approval regulations (e.g., CELEX:32007R0715, CELEX:32017R1151).
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DVLA: Engine Changes & MoT
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Regulation (EC) No 715/2007
Euro emissions framework for vehicle type approval.
Commission Regulation (EU) 2017/1151
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