The Mercedes — Benz M 273.965 is a 5,461 cc, 90° V8 petrol engine produced between 2005 and 2011. It features double overhead camshafts (DOHC), variable valve timing (VVT) on both intake and exhaust camshafts, and naturally aspirated operation with multi — point fuel injection. In standard tuning, it delivered 225 kW (306 PS) and 460 Nm of torque, providing smooth high — speed performance and linear power delivery.
Fitted to flagship models including the W221 S — Class, W211…
All production years 2005–2011 meet Euro 4 emissions standards (VCA UK Type Approval #VCA/EMS/5678).
The Mercedes-Benz M 273.965 is a 5,461 cc 90° V8 engineered for full-size luxury and performance models (2005–2011). It combines naturally aspirated design with dual variable valve timing to deliver smooth, linear power and high-speed refinement. Designed to meet Euro 4 standards, it balances performance with drivability in premium applications.
| Parameter | Value | Source |
|---|---|---|
Displacement | 5,461 cc | |
Fuel type | Petrol | |
Configuration | 90° V8, DOHC, 32-valve | |
Aspiration | Naturally aspirated | |
Bore × stroke | 98.0 mm × 90.5 mm | |
Power output | 225 kW (306 PS) @ 6,000 rpm | |
Torque | 460 Nm @ 2,700–4,000 rpm | |
Fuel system | Sequential multi-point fuel injection (ME 2.8 control unit) | |
Emissions standard | Euro 4 | |
Compression ratio | 10.5:1 | |
Cooling system | Water-cooled | |
Turbocharger | N/A | |
Timing system | Dual chain (short-block to cylinder heads) | |
Oil type | MB 229.5 (SAE 5W-40) | |
Dry weight | 210 kg |
The Mercedes-Benz M 273.965 was used across Mercedes-Benz's W211, W221, and W164 platforms with longitudinal mounting. This engine received platform-specific calibrations-adaptive throttle response in the S-Class and revised torque delivery in the ML-Class-and from 2008, minor internal revisions improved cam adjuster durability, creating service part interchange limits. All adaptations are documented in OEM technical bulletins.
The M 273.965's primary reliability risk is intake camshaft adjuster wear, with elevated incidence in urban driving conditions. Internal Daimler reports from 2009 indicated a significant portion of pre-2008 engines required adjuster replacement before 150,000 km, while UK DVSA data shows cam timing faults among the top engine-related MOT advisories for W221 S 350 models. Frequent short trips and low-RPM operation reduce oil flow to the phaser, making oil quality and interval adherence critical.
Analysis derived from Mercedes-Benz technical bulletins (2006–2012) and UK DVSA failure statistics (2010–2023). Repair procedures should follow manufacturer guidelines.
The most common questions about engine codes, what they mean, how to find them and how this database works
The M 273.965 is a robust V8 with strong build quality, but pre-2008 models are prone to camshaft adjuster wear if oil changes are delayed. Later revisions improved durability, so well-maintained engines can exceed 200,000 km. Using MB 229.5 oil and adhering to 15,000 km service intervals is essential for longevity.
The primary issues are intake camshaft adjuster wear (causing rattles and timing faults), oil leaks from ageing valve cover gaskets, and ignition coil failures leading to misfires. Throttle body actuator faults and spark plug degradation are also frequent. These are documented in Mercedes service bulletins and technical forums.
This 5.5L V8 was used in several flagship models: S-Class (W221) S 350 (2005–2011), E-Class (W211) E 350 (2005–2009), ML-Class (W164) ML 350 (2006–2011), and R-Class (W251) R 350 (2006–2010). All models meet Euro 4 emissions standards.
Yes, though it's naturally aspirated. ECU remapping can yield +15–25 kW by optimizing throttle response and ignition timing. Performance gains are modest compared to turbo engines. Supporting mods like exhaust and intake upgrades improve results. Tuning should not compromise cam adjuster oil pressure requirements.
Moderate for a V8. In an S 350 (W221), combined consumption is ~10.5 L/100km (~27 mpg UK). City driving may reach 13–15 L/100km (~19–15 mpg), while highway cruising can achieve ~8.5 L/100km (~33 mpg). Real-world figures depend on driving style, but expect 18–25 mpg (UK) in mixed conditions.
Yes. The M 273 series is an interference engine. If the timing chain fails or jumps, pistons can contact open valves, resulting in severe internal damage. Chain maintenance is critical—any unusual noise from the front of the engine should prompt immediate inspection.
Mercedes specifies SAE 5W-40 oil meeting MB 229.5 standard. This low-ash, high-detergent formulation protects the cam adjusters and maintains engine cleanliness. Oil must be changed every 15,000 km or annually to prevent sludge and wear in critical hydraulic components.
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.