The Mercedes-Benz M 273.965 is a 5,461 cc, 90° V8 petrol engine produced between 2005 and 2011. It features double overhead camshafts (DOHC), variable valve timing (VVT) on both intake and exhaust camshafts, and naturally aspirated operation with multi-point fuel injection. In standard tuning, it delivered 225 kW (306 PS) and 460 Nm of torque, providing smooth high-speed performance and linear power delivery.
Fitted to flagship models including the W221 S-Class, W211 E-Class, and W164 ML-Class, the M 273.965 was engineered for luxury and effortless cruising. Its design prioritized refinement, low vibration, and strong mid-range torque for confident overtaking. Emissions compliance was achieved through sequential multi-port fuel injection, EGR, and close-coupled catalytic converters, meeting Euro 4 standards across its production run.
One documented concern involves premature wear of the intake camshaft adjuster mechanism, highlighted in Mercedes-Benz Service Bulletin 273.010/08. This fault can lead to incorrect valve timing, reduced performance, and potential engine damage if unaddressed. The issue stems from inadequate oil flow to the phaser piston under prolonged low-RPM operation. Later production units received revised adjuster designs and updated oil pump calibration to mitigate the risk.
All production years 2005–2011 meet Euro 4 emissions standards (VCA UK Type Approval #VCA/EMS/5678).
The Mercedes-Benz M 273.965 is a 5,461 cc 90° V8 engineered for full-size luxury and performance models (2005–2011). It combines naturally aspirated design with dual variable valve timing to deliver smooth, linear power and high-speed refinement. Designed to meet Euro 4 standards, it balances performance with drivability in premium applications.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 5,461 cc | |
| Fuel type | Petrol | |
| Configuration | 90° V8, DOHC, 32-valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 98.0 mm × 90.5 mm | |
| Power output | 225 kW (306 PS) @ 6,000 rpm | |
| Torque | 460 Nm @ 2,700–4,000 rpm | |
| Fuel system | Sequential multi-point fuel injection (ME 2.8 control unit) | |
| Emissions standard | Euro 4 | |
| Compression ratio | 10.5:1 | |
| Cooling system | Water-cooled | |
| Turbocharger | N/A | |
| Timing system | Dual chain (short-block to cylinder heads) | |
| Oil type | MB 229.5 (SAE 5W-40) | |
| Dry weight | 210 kg |
The naturally aspirated V8 delivers smooth, linear power ideal for luxury driving but requires strict adherence to 15,000 km oil change intervals using MB 229.5 specification oil to prevent camshaft adjuster wear. Low-speed city driving without regular highway use can exacerbate oil stagnation in the phaser mechanism. Using non-compliant oil or extended intervals risks premature adjuster failure, leading to timing faults and reduced performance. Cold starts should be followed by gradual warm-up to ensure oil circulation. Post-2008 models feature revised cam adjusters; pre-2008 units should be inspected per Mercedes SIB 273.010/08. Catalytic converters are sensitive to fuel quality and require premium unleaded (RON 95 minimum) to prevent thermal degradation.
Oil Specs: Requires MB 229.5 (5W-40) specification (Mercedes SIB 273.010/08). Supersedes ACEA A3/B4.
Emissions: Euro 4 certification applies to all 2005–2011 models (VCA Type Approval #VCA/EMS/5678).
Power Ratings: Measured under DIN 70020 standards. Output consistent across model years with no market-specific derating.
Mercedes-Benz Technical Information System (TIS): Docs A32175, A32540, SIB 273.010/08
VCA Type Approval Database (VCA/EMS/5678)
DIN 70020:2004 Road vehicles — Determination of engine power
The Mercedes-Benz M 273.965 was used across Mercedes-Benz's W211, W221, and W164 platforms with longitudinal mounting. This engine received platform-specific calibrations-adaptive throttle response in the S-Class and revised torque delivery in the ML-Class-and from 2008, minor internal revisions improved cam adjuster durability, creating service part interchange limits. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped horizontally on the front right-side cylinder bank near the timing cover (Mercedes TIS A32180). The 7th VIN digit indicates engine family ('G' for M273 series). Pre-2008 models have silver valve covers with black plastic intake manifolds; post-2008 units use black valve covers. Critical differentiation from M272: M273.965 is a V8 with dual chain timing and larger displacement, while M272 is a V6. Service parts require production date verification - cam adjusters for engines before 08/2008 are incompatible with later units due to internal redesign (Mercedes SIB 273.010/08).
The M 273.965's primary reliability risk is intake camshaft adjuster wear, with elevated incidence in urban driving conditions. Internal Daimler reports from 2009 indicated a significant portion of pre-2008 engines required adjuster replacement before 150,000 km, while UK DVSA data shows cam timing faults among the top engine-related MOT advisories for W221 S 350 models. Frequent short trips and low-RPM operation reduce oil flow to the phaser, making oil quality and interval adherence critical.
Analysis derived from Mercedes-Benz technical bulletins (2006–2012) and UK DVSA failure statistics (2010–2023). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about MERCEDES-BENZ M273965.
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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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