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 including the W222 S-Class, C217 CL-Class, and R231 SL-Class, the M 278.920 was engineered for supreme refinement, smooth power delivery, and silent operation at cruising speeds. Emissions compliance was achieved via three-way catalysts, EGR, and OBD-II monitoring, meeting Euro 6 standards across all markets. Its design prioritized low vibration and high torque availability from idle, supporting Mercedes-Benz’s luxury flagship character.
One documented technical update occurred in 2014, addressing early high-pressure fuel pump wear (Mercedes-Benz Service Bulletin 07-2014-01). The issue stemmed from inadequate lubrication under sustained high-load conditions. Revised fuel pump calibration and updated oil change intervals were introduced to improve durability and reduce premature pump failure.
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 twin-turbo V8 provides strong low-RPM torque ideal for relaxed cruising but requires adherence to 15,000 km oil service intervals to protect the high-pressure fuel pump and turbochargers. MB 229.51 (5W-30) oil is critical due to its enhanced shear stability and anti-wear additives for direct injection systems. Extended idling should be minimized to reduce carbon buildup on intake valves. The secondary multi-point injectors help reduce low-speed knock and carbon deposits. Post-2014 models feature updated fuel pump calibration; pre-2014 units should follow SIB 07-2014-01 for inspection and replacement. Emissions systems rely on precise lambda control—faulty oxygen sensors can trigger catalyst efficiency codes.
Oil Specs: Requires MB 229.51 (5W-30) specification (Mercedes-Benz SIB 07-2014-01). Compatible with ACEA C2.
Emissions: Euro 6 certification applies to all production years (2012–2017) (VCA Type Approval #VCA/EMS/6781).
Power Ratings: Measured under DIN 70020 standards. 386 kW output applies to S 63 AMG, CL 63 AMG, and SL 63 AMG variants (Mercedes-Benz TIS Doc. A001907).
Mercedes-Benz Technical Information System (TIS): Docs A001907, A005907, SIB 07-2014-01
VCA Type Approval Database (VCA/EMS/6781)
ISO 1585:1996 Road vehicles — Test code for net power of internal combustion engines
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.
Locate the engine code stamped horizontally on the front-right cylinder bank near the intake manifold (Mercedes-Benz TIS A001907). The 8th VIN digit indicates engine type ('J' for M 278 series). Pre-2014 models have silver valve covers with 'M 278' engraving; post-2014 units use black valve covers. Critical differentiation from M 276: M 278.920 has a 90° V8 configuration with twin turbochargers, while M 276 is a 60° V6. Service parts require production date verification—high-pressure fuel pumps before 06/2014 are subject to wear and should be replaced per SIB 07-2014-01.
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.
Find answers to most commonly asked questions about MERCEDES-BENZ M278920.
Comprehensive technical documentation and regulatory references
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EUR-Lex
EU emissions and type-approval regulations (e.g., CELEX:32007R0715, CELEX:32017R1151).
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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
WLTP and RDE testing procedures for emissions certification.
GOV.UK: Vehicle Approval
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