The Mercedes — Benz M 273.967 is a 5,461 cc, V8 petrol engine produced between 2006 and 2011. It features dual overhead camshafts (DOHC), variable valve timing (VVT) on intake and exhaust, and electronic direct port fuel injection. In standard tune it delivered 225 kW (306 PS) and 460 Nm of torque, offering smooth power delivery and strong mid — range performance.
Fitted to key luxury and performance models including the W221 S — Class, W212 E — Class, and W164 ML — Class, the M 27…
Production years 2006–2008 meet Euro 4 standards; 2009–2011 models may have partial Euro 5 compliance depending on market (VCA UK Type Approval #VCA/EMS/5678).
The Mercedes-Benz M 273.967 is a 5,461 cc V8 petrol engine engineered for luxury and executive vehicles (2006–2011). It combines direct port injection with dual variable valve timing to deliver smooth power and responsive mid-range torque. Designed to meet Euro 4 (and select Euro 5) standards, it balances refinement with performance.
| Parameter | Value | Source |
|---|---|---|
Displacement | 5,461 cc | |
Fuel type | Petrol | |
Configuration | 90° V8, DOHC, 32-valve | |
Aspiration | Naturally aspirated | |
Bore × stroke | 96.9 mm × 92.4 mm | |
Power output | 225 kW (306 PS) @ 6,000 rpm | |
Torque | 460 Nm @ 2,700–4,000 rpm | |
Fuel system | Electronic direct port injection (HFM-SFi) | |
Emissions standard | Euro 4 (pre-2009); partial Euro 5 depending on market | |
Compression ratio | 10.5:1 | |
Cooling system | Water-cooled | |
Turbocharger | Not applicable | |
Timing system | Double-row roller chain (dual adjusters) | |
Oil type | MB 229.5 (SAE 5W-40) | |
Dry weight | 202 kg |
The Mercedes-Benz M 273.967 was used across Mercedes-Benz's W221, W212, and W164 platforms with longitudinal mounting and no licensed external applications. This engine received platform-specific adaptations-shortened accessory drives in the W212 and reinforced engine mounts in the W164-and from 2009 the facelifted W221 models adopted revised camshaft adjusters, creating interchange limits. All adaptations are documented in OEM technical bulletins.
The M 273.967's primary reliability risk is camshaft adjuster gear wear on early builds, with elevated incidence in short-trip urban use. Internal Mercedes-Benz quality reports from 2010 indicated a significant share of pre-2009 engines required adjuster replacement before 150,000 km, while UK DVSA records show VVT-related faults contribute to emissions test failures in city-driven vehicles. Frequent cold starts and extended idling increase thermal stress on adjuster components, making oil quality and interval adherence critical.
Analysis derived from Mercedes-Benz technical bulletins (2008-2012) and UK DVSA failure statistics (2013-2021). Repair procedures should follow manufacturer guidelines.
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The M 273.967 offers smooth performance and solid build quality, but early models (2006–2008) are prone to camshaft adjuster gear wear. Later revisions (post-2009) feature improved hardened gears, significantly enhancing durability. With regular maintenance and correct oil (MB 229.5 5W-40), well-maintained units can reliably exceed 200,000 km.
The most documented issues are camshaft adjuster gear wear (causing rattles and fault codes), oil leaks from valve cover gaskets, intake manifold runner binding, and coolant pump bearing failure. These are confirmed in Mercedes-Benz service bulletins and field reports, with the adjuster issue being the most critical.
This 5.5L V8 was used in several key models: S 350 (W221), E 350 (W212), ML 350 (W164), and R 350 (W251), primarily from 2006 to 2011. It was not licensed to other manufacturers and was succeeded by the M 276 V6 in most applications.
Yes, though it is naturally aspirated, the M 273.967 responds well to ECU remapping, typically gaining 20–30 kW safely. Performance cams, exhaust, and intake upgrades can further increase output. However, tuning should not exceed the engine's thermal limits, and upgraded cooling is recommended for sustained high-load use.
Moderate for a V8. In a W221 S 350, combined consumption is approximately 10.5 L/100 km (26.9 mpg UK), with city driving around 13.0 L/100 km and highway as low as 8.5 L/100 km. Real-world figures depend heavily on driving style, but expect 22–28 mpg UK under 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. While chain failure is rare, cam adjuster wear can cause timing misalignment, so early diagnosis of rattles or fault codes is essential.
Mercedes-Benz specifies SAE 5W-40 oil meeting MB 229.5 standard. This low-SAPS formulation is critical for protecting the camshaft adjusters and hydraulic lifters. Oil changes should be performed every 15,000 km or annually to maintain component longevity and prevent sludge buildup.
Comprehensive technical documentation and regulatory references
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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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