The Mercedes-Benz M275.981 is a 5,980 cc, V12 naturally aspirated petrol engine produced between 2006 and 2013. It features dual overhead camshafts (DOHC), variable valve timing (VVT), and multi-port fuel injection. In standard tuning, it delivered 368 kW (500 PS) with peak torque of 630 Nm, providing effortless high-speed performance and refinement for flagship luxury applications.
Fitted exclusively to the W221 S-Class and R230 SL-Class, the M275.981 was engineered for ultimate smoothness, silent operation, and linear power delivery. Emissions compliance was achieved through EGR and dual close-coupled three-way catalytic converters, allowing Euro 4 compliance across all production years in European markets.
One documented concern is premature camshaft adjuster wear observed in early production units, highlighted in Mercedes-Benz Service Bulletin 275.981-03/09. This issue is linked to inadequate oil flow regulation in the variable camshaft system under sustained low-RPM operation. From 2009, revised camshaft adjusters and updated engine control unit (ECU) mapping were implemented to stabilise oil pressure and reduce wear.
Production years 2006–2013 meet Euro 4 standards (VCA UK Type Approval #VCA/EMS/6789).
The Mercedes-Benz M275.981 is a 5,980 cc V12 naturally aspirated engine engineered for flagship luxury vehicles (2006–2013). It combines DOHC architecture with variable valve timing to deliver seamless power delivery and exceptional refinement. Designed to meet Euro 4 standards, it represents the pinnacle of Mercedes-Benz's naturally aspirated petrol engineering.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 5,980 cc | |
| Fuel type | Petrol | |
| Configuration | 60° V12, DOHC, 48-valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 82.6 mm × 93.0 mm | |
| Power output | 368 kW (500 PS) @ 5,300 rpm | |
| Torque | 630 Nm @ 2,700–4,000 rpm | |
| Fuel system | Sequential multi-port fuel injection | |
| Emissions standard | Euro 4 | |
| Compression ratio | 10.6:1 | |
| 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 | 238 kg |
The naturally aspirated V12 delivers linear throttle response ideal for relaxed cruising but requires consistent oil maintenance to prevent camshaft adjuster wear. MB 229.5 (5W-40) oil is essential due to its shear stability and anti-wear additives protecting the variable valve timing system. Extended idling or short-trip driving increases carbon buildup and oil degradation, so 15,000 km service intervals are recommended. The engine's sensitivity to fuel quality necessitates premium unleaded (RON 95 minimum) to maintain combustion efficiency and prevent knock. Post-2009 models feature revised cam adjusters; pre-2009 units should be inspected per Mercedes-Benz SIB 275.981-03/09. EGR and intake manifolds require periodic cleaning to sustain airflow and idle stability.
Oil Specs: Requires MB 229.5 (5W-40) specification (Mercedes-Benz SIB 275.981-03/09). Supersedes ACEA A3/B4.
Emissions: Euro 4 certification applies to all production years (2006–2013) (VCA Type Approval #VCA/EMS/6789).
Power Ratings: Measured under DIN 70020 standards. Output consistent across markets with premium fuel (Mercedes-Benz TIS Doc. A32120).
Mercedes-Benz Technical Information System (TIS): Docs A31380, A31650, SIB 275.981-03/09
VCA Type Approval Database (VCA/EMS/6789)
ISO 1585:1992 Road vehicles — Test code for net power of internal combustion engines
The Mercedes-Benz M275.981 was used across Mercedes-Benz's 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 2009 the updated camshaft adjuster system introduced in facelifted S-Class models improved oil pressure response, creating interchange limits. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped horizontally on the front timing cover near the harmonic balancer (Mercedes-Benz TIS A31380). The 7th and 8th VIN digits indicate engine type ('6A' for M275.981). Pre-2009 models have silver cam covers with black plastic intake manifolds; post-2009 units use black cam covers. Critical differentiation from M275.982: M275.981 has a 6.0L displacement and lacks twin-turbocharging. Service parts require production date verification—camshaft adjusters before 10/2008 are incompatible with later units due to internal redesign (Mercedes-Benz SIB 275.981-03/09).
The M275.981'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 2010 indicated a significant number of pre-2009 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 (2007-2013) and UK DVSA failure statistics (2010-2023). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about MERCEDES-BENZ M275981.
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DVLA: Engine Changes & MoT
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Regulation (EC) No 715/2007
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Commission Regulation (EU) 2017/1151
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