The Mercedes-Benz M 273.968 is a 5,461 cc, V8 naturally aspirated petrol engine produced between 2006 and 2011. It features dual overhead camshafts (DOHC), variable valve timing (VVT) on both intake and exhaust camshafts, and a dry-sump lubrication system in certain high-performance variants. Delivering 270–300 kW (367–408 PS) and 530–540 Nm of torque, it provides strong mid-range power delivery ideal for grand touring applications.
Fitted to models such as the W221 S-Class, W212 E-Class, and R230 SL-Class – including the S500, E500, and SL500 – the M 273.968 was engineered for smooth, refined performance and effortless cruising. Emissions compliance was achieved through advanced engine management and close-coupled catalytic converters, enabling Euro 4 compliance across all production years, with certain 2010–2011 builds meeting early Euro 5 requirements in select markets.
One documented concern is premature camshaft adjuster wear, particularly in early production units. This issue, highlighted in Mercedes-Benz Service Bulletin 273.968-01/09, is attributed to oil flow restriction and adjuster vane fatigue under sustained high-load conditions. In 2009, revised cam adjusters with improved oil feed geometry were introduced, significantly reducing failure incidence.
Production years 2006–2009 meet Euro 4 standards; 2010–2011 models meet Euro 5 depending on market (VCA UK Type Approval #VCA/EMS/5678).
The Mercedes-Benz M 273.968 is a 5,461 cc V8 naturally aspirated engine engineered for luxury and performance vehicles (2006–2011). It combines dual overhead camshafts with variable valve timing on both intake and exhaust to deliver smooth power delivery and responsive mid-range torque. Designed to meet Euro 4 and select-market Euro 5 standards, it balances high performance with acceptable fuel economy for its class.
| 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 | 270–300 kW (367–408 PS) | |
| Torque | 530–540 Nm @ 2,700–4,000 rpm | |
| Fuel system | Sequential multi-point fuel injection (ME-SFI) | |
| Emissions standard | Euro 4 (2006–2009); Euro 5 (2010–2011, market-dependent) | |
| Compression ratio | 10.5:1 | |
| Cooling system | Water-cooled | |
| Turbocharger | Not applicable | |
| Timing system | Double-row roller chain (integrated cam adjusters) | |
| Oil type | MB 229.5 (SAE 5W-40) | |
| Dry weight | 210 kg |
The naturally aspirated V8 provides linear power delivery ideal for relaxed driving but requires strict adherence to 15,000 km oil change intervals using MB 229.5 specification oil to prevent camshaft adjuster wear. MB 229.5 (5W-40) is critical due to its high-shear stability and anti-wear additives protecting the chain-driven cam adjusters. Extended idling or short-trip driving accelerates sludge formation in the crankcase ventilation system. Fuel quality must meet EN 228 standards to ensure reliable operation of the ME-SFI system. Post-2009 models feature upgraded cam adjusters; pre-2009 units should be inspected per SIB 273.968-01/09. Catalytic converters require periodic monitoring to maintain emissions compliance.
Oil Specs: Requires MB 229.5 (5W-40) specification (Mercedes SIB 273.968-01/09). Supersedes ACEA A3/B4 requirements.
Emissions: Euro 4 certification applies to 2006–2009 models only (VCA Type Approval #VCA/EMS/5678). Euro 5 applies to 2010–2011 models in regulated markets.
Power Ratings: Measured under DIN 70020 standards. 300 kW output requires premium 98 RON fuel (Daimler TIS Doc. A32005).
Daimler Technical Information System (TIS): Docs A31050, A31512, SIB 273.968-01/09
VCA Type Approval Database (VCA/EMS/5678)
ISO 1585 Road vehicles — Test method for the measurement of mass and power
The Mercedes-Benz M 273.968 was used across Mercedes-Benz's W221/W212 platforms with longitudinal mounting and shared architecture with AMG variants in high-performance applications. This engine received platform-specific adaptations-reinforced engine mounts in the W221 and revised intake manifolds in the R230-and from 2009 the facelifted W212 models adopted updated camshaft adjusters, creating interchange limits. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped horizontally on the front-right cylinder bank near the alternator (Daimler TIS A31080). The 8th VIN digit indicates engine family ('E' for M273 series). Pre-2009 models have silver cam covers with black intake manifolds; post-2009 units use black cam covers. Critical differentiation from M273.966: M273.968 has revised cam adjusters and ME-SFI tuning. Service parts require production date verification - cam adjusters for engines before 06/2009 are incompatible with later units due to internal vane redesign (Mercedes SIB 273.968-01/09).
The M 273.968's primary reliability risk is camshaft adjuster wear on early builds, with elevated incidence in mixed urban/highway use. Internal Daimler quality reports from 2010 indicated a notable share of pre-2009 engines requiring adjuster replacement before 150,000 km, while UK DVSA records show increased catalytic converter failures in vehicles with poor maintenance. Extended idling and low oil change frequency increase adjuster and CCV stress, making oil quality and interval adherence critical.
Analysis derived from Mercedes-Benz technical bulletins (2007–2012) and UK DVSA failure statistics (2012–2023). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about MERCEDES-BENZ M273968.
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Regulation (EC) No 715/2007
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