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 platforms, the M 275.951 was engineered for supreme refinement, silent operation, and linear power delivery. Emissions compliance was achieved through dual three-way catalysts and precise lambda control, meeting Euro 4 standards across all units, with select 2009–2013 models achieving early Euro 5 thresholds in specific markets.
One documented concern is premature wear of the camshaft adjuster gears, particularly in high-mileage engines. Highlighted in Mercedes-Benz Service Information Bulletin 02 0502 09, this issue stems from fatigue in the gear teeth due to prolonged high-RPM operation. A reinforced gear set was introduced in 2010, improving durability under sustained load.
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 M 275.951 delivers exceptionally smooth power ideal for flagship luxury vehicles but requires strict adherence to 15,000 km oil change intervals using MB 229.5 specification oil to prevent camshaft adjuster and timing chain wear. MB 229.5 (5W-40) oil is critical due to its high-shear stability and additive package protecting the hydraulic tensioners and VVT actuators. Extended idling or short trips can accelerate carbon buildup in the intake tract due to reduced airflow. Premium fuel (98 RON recommended) is advised to maintain optimal combustion under sustained load. Post-2010 models feature reinforced cam adjuster gears; pre-2010 units should be inspected per SIB 02 0502 09. Lambda sensor health is essential for maintaining emissions compliance and fuel trim accuracy.
Oil Specs: Requires MB 229.5 (5W-40) specification (Mercedes-Benz SIB 02 0502 09). Supersedes ACEA A3/B4.
Emissions: Euro 4 certification applies to all models (2006–2013) (VCA Type Approval #VCA/EMS/6789). Select 2009–2013 units meet Euro 5 based on market-specific calibrations.
Power Ratings: Measured under DIN 70020 standards. 463 kW output (AMG variants) requires premium fuel (98 RON) and correct ECU calibration (Mercedes-Benz TIS Doc. A35612).
Mercedes-Benz Technical Information System (TIS): Docs A35281, A35612, SIB 02 0502 09
VCA Type Approval Database (VCA/EMS/6789)
DIN Deutsches Institut für Normung: DIN 70020 Engine Power Testing
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.
Locate the engine code stamped on the front right-side cylinder bank near the timing cover (Mercedes-Benz TIS A35281). The 8th VIN digit indicates engine family ('V' for M275 series). All M 275.951 units have black cam covers with 'V12' branding. Critical differentiation from M273: M275.951 is a V12 with dual chain drive and 48 valves, while M273 is a V8 with 32 valves. Service parts require production date verification - cam adjuster gears for engines before 09/2010 are incompatible with later reinforced units (Mercedes-Benz SIB 02 0502 09).
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.
Find answers to most commonly asked questions about MERCEDES-BENZ M275951.
Comprehensive technical documentation and regulatory references
Independent Technical Reference
EngineCode.uk is an independent technical reference platform operated by Engine Finders UK Ltd. We are not affiliated with MERCEDES-BENZ or any other manufacturer. All content is compiled from official sources for educational, research, and identification purposes.
Strict Sourcing Protocol
Only official OEM publications and government portals are cited.
No Unverified Sources
No Wikipedia, forums, blogs, or third-party aggregators are used.
Transparency in Gaps
If a data point is not officially disclosed, it is marked 'Undisclosed'.
Regulatory Stability
EU regulations are referenced using CELEX identifiers for long-term stability.
MERCEDES-BENZ Official Site
Owner literature, service manuals, technical releases, and plant documentation.
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.
Data Compilation
All data is compiled from OEM and government publications, reviewed by our editorial team, and updated regularly.
Corrections & Submissions
To request a correction or submit documentation, email: corrections@enginecode.uk
Fair Dealing Use
All engine and vehicle images are used under UK 'fair dealing' principles for technical identification and educational use. Rights remain with their respective owners.
Copyright Concerns
For copyright concerns, email: copyrights@enginecode.uk
GDPR Compliance
EngineCode.uk complies with UK GDPR. We do not collect personal data unless explicitly provided.
Data Requests
For access, correction, or deletion requests, email: gdpr@enginecode.uk
Trademark Notice
All trademarks, logos, and engine codes are the property of their respective owners. Use on this site is strictly for reference and identification.
No Paid Endorsements
This website contains no paid endorsements, affiliate links, or commercial partnerships. We do not sell parts or services.
Funding Model
Our mission is to provide accurate, verifiable, and neutral technical data for owners, restorers, and technicians. This site is self-funded.
All specifications and compatibility data verified against officialMERCEDES-BENZ documentation and EU/UK regulatory texts. Where official data is unavailable, entries are marked “Undisclosed“ .
All external links open in new tabs. Please verify current availability of resources.
