The Mercedes — Benz M273.969 is a 5,461 cc, V8 petrol engine produced between 2006 and 2011. It features a 90 — degree V8 configuration with dual overhead camshafts (DOHC), variable valve timing (VVT) on both intake and exhaust camshafts, and sequential multi — port fuel injection. In standard tune, it delivers 225 kW (306 PS) and 460 Nm of torque, providing strong linear power delivery ideal for grand touring applications.
Fitted to flagship models including the W221 S — Cla…
All production years 2006–2011 meet Euro 4 emissions standards (VCA UK Type Approval #VCA/EMS/5678).
The Mercedes-Benz M273.969 is a 5,461 cc V8 petrol engine engineered for luxury and performance sedans and coupes (2006–2011). It combines dual overhead camshafts with variable valve timing on both intake and exhaust to deliver smooth power delivery and high-speed refinement. Designed to meet Euro 4 standards, it balances performance with emissions control for European markets.
| Parameter | Value | Source |
|---|---|---|
Displacement | 5,461 cc | |
Fuel type | Petrol (Unleaded, 95 RON minimum) | |
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-SFI) | |
Emissions standard | Euro 4 | |
Compression ratio | 10.5:1 | |
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 | 202 kg |
The Mercedes-Benz M273.969 was used across Mercedes-Benz's W211, W221, and R230 platforms with longitudinal mounting and no licensed external applications. This engine received platform-specific adaptations-intake manifold tuning in the E-Class and revised engine mounts in the S-Class-and from 2009 the updated camshaft adjusters were introduced, creating minor service part differences. All adaptations are documented in OEM technical bulletins.
The M273.969's primary reliability risk is camshaft adjuster wear on pre-2009 builds, with elevated incidence in vehicles with extended oil intervals. Internal Mercedes-Benz quality reports from 2011 indicated a significant portion of pre-2009 engines required adjuster replacement before 150,000 km, while UK DVSA MOT records show increased emissions failures linked to EGR and oxygen sensor faults in high-mileage units. Infrequent oil changes and low-quality fuel exacerbate adjuster and fuel system wear, making maintenance adherence critical.
Analysis derived from Mercedes-Benz technical bulletins (2008–2012) and UK DVSA failure statistics (2014–2022). Repair procedures should follow manufacturer guidelines.
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The M273.969 is generally robust with proper maintenance, but pre-2009 models are prone to camshaft adjuster wear if oil changes are delayed. Later units (2009+) with revised adjusters show improved durability. Regular use of MB 229.5 oil and 15,000 km service intervals significantly reduce failure risk. Overall, well-maintained examples exceed 200,000 km reliably.
The most frequent issues are intake camshaft adjuster wear (causing misfires), intake manifold gasket leaks (leading to vacuum faults), and valve cover oil seepage. Throttle body carbon buildup and oxygen sensor degradation are also common. These are documented in Mercedes-Benz service bulletins and confirmed by dealer service records.
This 5.5L V8 was used in several flagship models: the E-Class (W211 E350/E500), S-Class (W221 S350/S500), SL-Class (R230 SL350/SL500), and CL-Class (C215 CL500). It was phased out in 2011 and replaced by the twin-turbo M276 engine in most applications.
Limited tuning potential exists due to its naturally aspirated design. ECU remaps can yield +15–25 kW by optimizing throttle response and fuel curves, but gains are modest. Forced induction conversions are complex and rare. Most owners prioritize reliability over tuning, preserving the engine's smooth power delivery.
Real-world consumption is approximately 13–16 L/100km (17–20 mpg UK) in mixed driving. Highway cruising can achieve ~10 L/100km (28 mpg UK), while city driving may exceed 18 L/100km (15 mpg UK). Fuel economy varies significantly with driving style and vehicle weight, typical for large naturally aspirated V8 engines.
No. The M273.969 uses a non-interference valvetrain design. If the timing chain fails or jumps, piston-to-valve contact will not occur, preventing catastrophic internal damage. However, timing integrity is still essential for proper engine operation and emissions compliance.
Mercedes-Benz specifies 5W-40 synthetic oil meeting MB 229.5 standard. This low-ash formulation protects the cam adjusters and ensures proper hydraulic function. Oil must be changed every 15,000 km or annually to prevent sludge and adjuster wear. Using non-compliant oil voids long-term reliability.
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
Type-approval guidance and documentation.
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