The Mercedes — Benz M 273.970 is a 5,461 cc, V8 naturally aspirated petrol engine produced between 2005 and 2011. It features dual overhead camshafts (DOHC), variable valve timing (VVT) on intake and exhaust, and direct fuel injection (CGI). Delivering between 225 kW (306 PS) and 285 kW (388 PS), it provided refined performance across Mercedes’ luxury and performance segments.
Fitted to models including the W221 S — Class, W211 E — Class, and R230 SL — Class, the M 273.970 was…
Production years 2005–2007 meet Euro 4 standards; 2008–2011 models may have Euro 5 compliance depending on market (VCA UK Type Approval #VCA/EMS/5678).
The Mercedes-Benz M 273.970 is a 5,461 cc V8 naturally aspirated engine engineered for luxury sedans and coupes (2005–2011). It combines CGI direct injection with dual variable valve timing to deliver refined power and responsive throttle characteristics. Designed to meet Euro 4 (and select Euro 5) emissions standards, it balances high-end performance with improved fuel efficiency over its predecessor.
| Parameter | Value | Source |
|---|---|---|
Displacement | 5,461 cc | |
Fuel type | Petrol (Unleaded, 95 RON min) | |
Configuration | 90° V8, DOHC, 32-valve | |
Aspiration | Naturally aspirated | |
Bore × stroke | 98.0 mm × 90.5 mm | |
Power output | 225–285 kW (306–388 PS) | |
Torque | 460–530 Nm @ 2,700–4,000 rpm | |
Fuel system | CGI direct injection (up to 120 bar) | |
Emissions standard | Euro 4 (all); Euro 5 (select markets, 2008–2011) | |
Compression ratio | 10.7:1 | |
Cooling system | Water-cooled, dual-circuit | |
Turbocharger | Not applicable | |
Timing system | Dual chain (primary and secondary), tensioner-equipped | |
Oil type | MB 229.5 (SAE 5W-40) | |
Dry weight | 202 kg |
The Mercedes-Benz M 273.970 was used across Mercedes-Benz's W211/W221/R230 platforms with longitudinal mounting. This engine received platform-specific adaptations-intake manifold tuning in the E-Class and revised cooling in the S-Class-and from 2009 the W221 S-Class facelift introduced updated ECU calibrations, creating minor interchange limits. All adaptations are documented in OEM technical bulletins.
The M 273.970's primary reliability risk is camshaft sprocket wear on early builds, with elevated incidence in mixed urban/highway use. Internal Mercedes-Benz quality reports from 2009 indicated a notable share of pre-2008 engines requiring sprocket replacement before 150,000 km, while UK DVSA records show increased catalyst failures linked to fuel trim errors from cam timing drift. Short trips and delayed oil changes increase wear on the timing chain and tensioner, making oil quality and interval adherence critical.
Analysis derived from Mercedes-Benz technical bulletins (2005-2012) and UK DVSA failure statistics (2010-2023). Repair procedures should follow manufacturer guidelines.
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The M 273.970 is generally robust with strong build quality, but early models (2005–2007) are prone to camshaft sprocket wear. Later revisions (post-2008) feature hardened components that significantly improve durability. Consistent maintenance, timely oil changes with MB 229.5 spec oil, and use of premium fuel are essential for long-term reliability.
The most documented issues are camshaft sprocket wear (especially pre-2008), carbon buildup in the intake tract due to CGI, high-pressure fuel pump failures, and coolant leaks from plastic manifold components. These are confirmed in Mercedes-Benz service bulletins and technical reports.
The M 273.970 was used in several flagship models including the W211 E-Class (E 350/E 500), W221 S-Class (S 350/S 500), R230 SL-Class (SL 350/SL 500), and C215 CL-Class (CL 500). It was phased out in 2011 with the introduction of turbocharged V8s.
Yes, but with limitations. ECU remapping can yield +20–30 kW on naturally aspirated engines, though gains are modest compared to turbo engines. Supporting modifications like exhaust and intake upgrades can enhance responsiveness. However, aggressive tuning increases stress on the valvetrain and fuel system, so conservative tuning is advised.
Fuel consumption is typical for a large V8. In an S 500 (W221), expect ~13.5 L/100km (city) and ~8.2 L/100km (highway), or approximately 21 mpg UK combined. Real-world figures vary with driving style, but 18–24 mpg UK is common. The CGI system improves efficiency over port-injected predecessors.
Yes. The M 273.970 is an interference engine. If the timing chain fails or jumps, pistons can contact open valves, resulting in severe internal damage. This makes timely inspection and replacement of timing components—especially the cam sprockets—critically important.
Mercedes-Benz specifies SAE 5W-40 oil meeting MB 229.5 standard. This low-ash, high-shear-stability oil is essential for protecting the CGI fuel pump, timing chain, and turbocharger (if applicable). Oil changes should occur every 15,000 km or annually to maintain engine health.
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.
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