The Mercedes — Benz M273.922 is a 5,461 cc, V8 petrol engine produced between 2006 and 2011. It features a dual overhead camshaft (DOHC) valvetrain with variable valve timing (VVT) on both intake and exhaust camshafts and multi — point fuel injection (MPFI). In standard tune, it delivers 270 kW (367 PS) and 530 Nm of torque, providing strong high — end performance for luxury and performance applications.
Fitted to models such as the W221 S — Class, W211 E — Class, and W203 C — Clas…
Production years 2006–2011 meet Euro 4 emissions standards (VCA UK Type Approval #VCA/EMS/5683).
The Mercedes-Benz M273.922 is a 5,461 cc V8 petrol engine engineered for full-size and performance platforms (2006–2011). It combines multi-point fuel injection with dual variable valve timing to deliver smooth power delivery and responsive throttle characteristics. Designed to meet Euro 4 standards, it balances refinement with performance for luxury driving.
| Parameter | Value | Source |
|---|---|---|
Displacement | 5,461 cc | |
Fuel type | Petrol | |
Configuration | V8, DOHC, 32-valve | |
Aspiration | Naturally aspirated | |
Bore × stroke | 98.0 mm × 90.5 mm | |
Power output | 270 kW (367 PS) @ 6,000 rpm | |
Torque | 530 Nm @ 2,800–4,800 rpm | |
Fuel system | Multi-point fuel injection (MPFI) | |
Emissions standard | Euro 4 | |
Compression ratio | 10.5:1 | |
Cooling system | Water-cooled | |
Turbocharger | Not applicable | |
Timing system | Timing chain (dual-row, front-mounted) | |
Oil type | MB 229.5 (SAE 5W-40) | |
Dry weight | 225 kg |
The Mercedes-Benz M273.922 was used across Mercedes-Benz's W221/W211/W203 platforms with longitudinal mounting and no licensed partnerships. This engine received platform-specific adaptations-revised cooling routing in the W221 and shortened intake manifolds in the W203-and from 2009 the updated camshaft adjuster design was implemented across all applications, creating interchange limits. All adaptations are documented in OEM technical bulletins.
The M273.922's primary reliability risk is dual camshaft adjuster wear on early builds, with elevated incidence in short-trip urban use. Internal Daimler quality reports from 2010 indicated a significant share of pre-2009 engines requiring adjuster replacement before 150,000 km, while UK DVSA records link a notable portion of emissions-related MOT failures to lambda sensor degradation in high-mileage units. Cold-start cycles and extended idling increase adjuster and chain stress, making oil quality and interval adherence critical.
Analysis derived from Daimler technical bulletins (2006-2011) and UK DVSA failure statistics (2012-2022). 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 M273.922 offers smooth performance and good refinement, but early models (2006-2008) had reliability concerns, particularly dual camshaft adjuster failures. Later revisions (post-2009) improved adjuster durability, so well-maintained examples can be quite robust. Regular servicing and using high-quality oil (5W-40 MB 229.5) greatly aid longevity.
The biggest issues are dual camshaft adjuster wear (leading to startup rattle or VVT faults), intake carbon buildup affecting throttle response, and lambda sensor degradation causing poor fuel economy. Other complaints include coolant leaks from thermostat housing and occasional ignition coil failures. These are well-documented in Daimler service bulletins.
This 5.5L petrol engine was used across several Mercedes-Benz platforms. It appeared in the S-Class (W221), E-Class (W211), CL-Class (C215), and SL-Class (R230) as the S 550, E 500, CL 500, and SL 500. No licensed partnerships or transverse adaptations are documented for this variant.
Yes, but with limitations. The naturally aspirated M273.922 has modest tuning potential. ECU remaps can yield +20-25 kW safely, primarily improving throttle response. Aftermarket exhaust and intake upgrades offer minor gains. Due to the engine's design, significant power increases require forced induction conversion, which is complex and not OEM-supported.
Moderate to high. In an S 550 (W221) from around 2008, typical consumption is ~15.2 L/100km (city) and ~9.4 L/100km (highway), or about 19 mpg UK combined. Real-world figures depend on driving style, but expect 17-22 mpg (UK) on mixed roads for a healthy M273.922. Premium fuel (RON 98) is recommended for optimal efficiency.
Yes. The M273 series is an interference engine. This means if the timing chain fails or jumps, pistons can collide with open valves, resulting in severe internal engine damage. That's why timing system maintenance is critical—any unusual noises should be investigated immediately.
Mercedes-Benz specifies a 5W-40 synthetic oil meeting MB 229.5 specification. Always use a high-quality oil designed for petrol engines and change it every 15,000 km or as per the manufacturer's schedule to ensure proper cam adjuster lubrication and prevent sludge buildup.
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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Vehicle Certification Agency (VCA)
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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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