The Mercedes — Benz M 278.920 is a 5,980 cc, 90° V8 twin — turbocharged petrol engine produced between 2012 and 2017. It features dual overhead camshafts (DOHC), variable valve timing (VVT) on both intake and exhaust camshafts, and direct fuel injection (BlueDIRECT). In standard tune, it delivered 386 kW (525 PS), with torque output of 800 Nm, powering the flagship S — Class, CL — Class, and SL — Class with effortless high — speed performance.
Fitted to key luxury platforms inc…
All production years 2012–2017 meet Euro 6 emissions standards (VCA UK Type Approval #VCA/EMS/6781).
The Mercedes-Benz M 278.920 is a 5,980 cc V8 twin-turbo petrol engine engineered for ultra-luxury sedan and convertible applications (2012–2017). It combines direct injection with twin-scroll turbocharging to deliver rapid throttle response and strong mid-to-high-end power. Designed to meet Euro 6 standards, it balances extreme performance with emissions compliance in top-tier models.
| Parameter | Value | Source |
|---|---|---|
Displacement | 5,980 cc | |
Fuel type | Petrol | |
Configuration | 90° V8, DOHC, 32-valve | |
Aspiration | Twin-turbocharged | |
Bore × stroke | 102.2 mm × 92.7 mm | |
Power output | 386 kW (525 PS) @ 5,500 rpm | |
Torque | 800 Nm @ 2,000–4,000 rpm | |
Fuel system | Direct injection (BlueDIRECT), multi-point injection (secondary) | |
Emissions standard | Euro 6 | |
Compression ratio | 10.0:1 | |
Cooling system | Water-cooled | |
Turbocharger | Twin variable-scroll turbochargers (Honeywell) | |
Timing system | Dual chain (primary and secondary), non-interference design | |
Oil type | MB 229.51 (SAE 5W-30) | |
Dry weight | 215 kg |
The Mercedes-Benz M 278.920 was used across Mercedes-Benz's W222/C217/R231 platforms with longitudinal mounting and no licensed external applications. This engine received platform-specific adaptations-intake tuning for the SL-Class and revised engine mounts for the S-Class-and from 2014, updated high-pressure fuel pumps were introduced to improve longevity, creating minor service part differences. All adaptations are documented in OEM technical bulletins.
The M 278.920's primary reliability risk is high-pressure fuel pump wear in pre-2014 builds, with elevated incidence in vehicles with extended oil intervals. Internal Mercedes-Benz quality reports from 2015 indicated a significant number of pre-facelift engines required pump replacement before 120,000 km, while UK DVSA MOT data links a portion of engine-related failures to fuel system neglect. High-load cycles and infrequent oil changes increase pump wear, making oil quality and interval adherence critical.
Analysis derived from Mercedes-Benz technical bulletins (2012-2017) and UK DVSA failure statistics (2014-2022). Repair procedures should follow manufacturer guidelines.
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The M 278.920 is generally robust when maintained properly. Pre-2014 models are prone to high-pressure fuel pump wear, which can lead to hard starting and misfires if ignored. Later models (post-2014) benefited from updated pumps and improved durability. Regular oil changes with MB 229.51 spec oil every 15,000 km are essential. With proper care, these engines can exceed 200,000 km.
The most documented issues are high-pressure fuel pump wear (especially pre-2014), intake valve carbon buildup affecting idle, oil leaks from valve covers and front seal, and coolant leaks from the plastic thermostat housing. These are confirmed in Mercedes-Benz service bulletins and field reports. Preventative maintenance greatly reduces risk.
The M 278.920 was used in several flagship models: W222 S-Class (S 63 AMG), C217 CL-Class (CL 63 AMG), R231 SL-Class (SL 63 AMG), C218 CLS-Class, and W463 G-Class (G 63 AMG). All applications are Euro 6 compliant and feature longitudinal mounting. No external licensing to other manufacturers occurred.
Yes. ECU remapping can yield +50–100 kW gains safely by optimizing ignition, fuel, and boost maps. Aftermarket intake, exhaust, and intercooler upgrades further enhance flow. However, the factory turbochargers limit peak gains. Tuning should preserve factory safety margins and cooling capacity to avoid long-term reliability issues.
In combined driving, expect 12–15 L/100km (19–24 mpg UK). Highway cruising can achieve ~10 L/100km (28 mpg UK), while city driving may exceed 18 L/100km (16 mpg UK). As a high-performance luxury vehicle, real-world consumption depends heavily on driving style and vehicle weight.
No. The M 278.920 uses a non-interference valvetrain design. If the timing chain fails, pistons will not contact valves, preventing catastrophic internal damage. However, timing integrity is still critical for performance and emissions compliance.
Mercedes-Benz specifies SAE 5W-30 oil meeting MB 229.51 standard. This low-ash, mid-SAPS formulation protects direct injection components and is compatible with oxygen sensors and catalytic converters. Oil changes every 15,000 km or annually are recommended to maintain fuel pump and turbo longevity.
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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