The Mercedes — Benz M273.963 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), and sequential multi — port fuel injection. In standard tuning, it delivered 225 kW (306 PS) with peak torque of 460 Nm, providing strong mid — range performance for grand touring applications.
Fitted to flagship models such as the W221 S — Class, W211 E — Class, and R230 SL — Class, the M273.96…
Production years 2005–2011 meet Euro 4 standards (VCA UK Type Approval #VCA/EMS/5678).
The Mercedes-Benz M273.963 is a 5,461 cc V8 naturally aspirated engine engineered for luxury and executive vehicles (2005–2011). It combines dual overhead camshafts with variable valve timing to deliver smooth, linear power delivery. Designed to meet Euro 4 standards, it balances high-end performance with drivability and refinement.
| 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 | Sequential multi-port fuel injection | |
Emissions standard | Euro 4 | |
Compression ratio | 10.7:1 | |
Cooling system | Water-cooled | |
Turbocharger | Not applicable | |
Timing system | Dual chain (primary and secondary), non-interference design | |
Oil type | MB 229.5 (SAE 5W-40) | |
Dry weight | 210 kg |
The Mercedes-Benz M273.963 was used across Mercedes-Benz's W211/W221/R230 platforms with longitudinal mounting and no licensed external applications. This engine received platform-specific adaptations-intake manifold tuning in the SL-Class and revised cooling routing in the S-Class-and from 2008 the updated camshaft adjuster system introduced in facelifted E-Class models improved oil pressure response, creating interchange limits. All adaptations are documented in OEM technical bulletins.
The M273.963's primary reliability risk is camshaft wear in early builds, with elevated incidence in urban and low-RPM driving. Internal Mercedes-Benz quality reports from 2009 indicated a significant number of pre-2008 engines requiring camshaft replacement before 150,000 km, while UK DVSA records show intake-related faults contributing to emissions test failures. Extended idling and short-trip usage reduce oil pressure stability, making adherence to oil specification and service intervals critical.
Analysis derived from Mercedes-Benz technical bulletins (2006-2012) and UK DVSA failure statistics (2010-2023). 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 M273.963 offers smooth performance and robust construction, but early models (2005–2007) are prone to camshaft wear if maintenance is deferred. Post-2008 revisions resolved most oil pressure issues, so well-maintained examples exceed 200,000 km. Using correct MB 229.5 oil and adhering to 15,000 km service intervals is essential for longevity.
Primary issues include camshaft wear (especially pre-2008), intake manifold flap failure, valve cover oil leaks, and ignition coil misfires. These are documented in Mercedes-Benz service bulletins. Carbon buildup and EGR faults are less common than in diesel variants but may occur with poor maintenance.
This 5.5L V8 was used in several flagship models: E-Class (W211 E350/E500), S-Class (W221 S350/S500), CL-Class (C216 CL500), and SL-Class (R230 SL350/SL500). All applications are petrol-powered and Euro 4 compliant. No cross-manufacturer usage is documented.
Yes, though gains are more limited than turbocharged engines. ECU remapping can yield +15–25 kW safely by optimizing ignition and fuel maps. Supporting mods like high-flow intake and exhaust improve responsiveness. However, the naturally aspirated design limits peak output, and tuning should not compromise valve timing stability.
Moderate for a V8. In an S500 (W221), combined consumption is ~11.5 L/100km (~24.5 mpg UK). City driving may exceed 14 L/100km, while highway runs can achieve ~9.0 L/100km (~31 mpg UK). Real-world economy depends heavily on driving style, but expect 20–25 mpg (UK) under mixed conditions.
No. The M273.963 uses a non-interference valvetrain design. If the timing chain fails, piston-to-valve contact is avoided, preventing catastrophic internal damage. However, timing chain replacement is still recommended at 180,000 km or as per service schedule to maintain synchronization.
Mercedes-Benz specifies SAE 5W-40 oil meeting MB 229.5 standard. This synthetic oil provides optimal protection for the variable camshaft system and high-temperature stability. Change intervals should not exceed 15,000 km or one year to prevent sludge and wear.
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
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