The Mercedes-Benz M257.930 is a 2,999 cc, inline-six, turbocharged petrol engine produced between 2017 and 2023. It features a 24-valve, DOHC configuration with direct fuel injection, EQ Boost integrated starter-generator, and twin-scroll turbocharging. This electrified engine delivers strong low-end torque and rapid throttle response, characteristic of Mercedes-Benz's M256/M257 engine family.
Fitted to the W222 S-Class (S 560), W223 S-Class (S 500), and V222 S-Class Long (S 560 L), the M257.930 was engineered for high-speed stability, smooth power delivery, and enhanced efficiency through mild hybrid assistance. Emissions compliance was achieved through close-coupled catalytic converters and closed-loop lambda control, allowing Euro 6d compliance across its production run.
One documented concern is premature high-pressure fuel pump wear, particularly in early production units. This issue, highlighted in Mercedes-Benz Service Information Bulletin 07.0128, is attributed to contamination from degraded fuel system components. Later builds (post-2020) received revised pump internals and improved filtration, enhancing long-term reliability.
All production years 2017–2023 meet Euro 6d emissions standards (VCA UK Type Approval #VCA/EMS/5687).
The Mercedes-Benz M257.930 is a 2,999 cc inline-six turbocharged petrol engine engineered for flagship luxury sedans (2017–2023). It combines direct fuel injection with an EQ Boost integrated starter-generator and twin-scroll turbocharger to deliver seamless power delivery. Designed to meet Euro 6d standards, it balances performance with electrified efficiency.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 2,999 cc | |
| Fuel type | Petrol | |
| Configuration | Inline-6, DOHC, 24-valve | |
| Aspiration | Turbocharged | |
| Bore × stroke | 83.0 mm × 92.0 mm | |
| Power output | 340 kW (462 PS) @ 5,250–6,000 rpm | |
| Torque | 700 Nm @ 1,600–4,000 rpm | |
| Fuel system | Direct injection (Bosch HDEV6, 350 bar) with EQ Boost | |
| Emissions standard | Euro 6d | |
| Compression ratio | 10.5:1 | |
| Cooling system | Water-cooled | |
| Turbocharger | Single twin-scroll turbo (ball-bearing, BorgWarner) | |
| Timing system | Double-row roller chain (rear-mounted) | |
| Oil type | 0W-40 (MB 229.52) | |
| Dry weight | 209 kg |
The turbocharged inline-six with EQ Boost provides seamless power delivery ideal for luxury driving but requires strict adherence to 15,000 km oil change intervals using MB 229.52-specified 0W-40 oil to maintain turbo and bearing integrity. High-RPM operation demands consistent oil pressure; dry-sump system failure can lead to catastrophic engine damage. The HDEV6 fuel system is robust but sensitive to fuel quality. Post-2020 engines benefit from upgraded high-pressure fuel pumps and filtration per AMG Technical Bulletin 07.0128. Catalytic converters require premium unleaded fuel meeting EN 228 to prevent thermal degradation and backpressure issues.
Oil Specs: Requires MB 229.52 specification (Mercedes AMG TB 07.0128). 0W-40 viscosity critical for high-temperature turbo and bearing protection.
Emissions: Euro 6d certification applies to all 2017–2023 models (VCA Type Approval #VCA/EMS/5687). No market-specific variants.
Power Ratings: Measured under DIN 70020 standards. Output consistent across all markets (Mercedes Group PT-2017).
Mercedes-Benz Technical Information System (TIS): Docs A33768, A34030, AMG TB 07.0128
VCA Type Approval Database (VCA/EMS/5687)
DIN Deutsches Institut für Normung: DIN 70020 Power Measurement Standard
The Mercedes-Benz M257.930 was used across Mercedes-Benz's W222/W223/V222 platforms with longitudinal mounting. This engine received platform-specific tuning-adapted throttle response in the W223 and revised cooling layouts in the W222-and from 2020, updated high-pressure fuel pump internals and filtration per AMG TB 07.0128, creating service part interchange limits. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped vertically on the right-side engine block near the oil filter housing (Mercedes TIS A33818). The 8th VIN digit indicates engine type ('M' for M257 series). All units have black cam covers with silver Mercedes-Benz lettering. Critical differentiation from M256.980: M257.930 has a lower power output and revised EQ Boost calibration, while M256.980 is tuned for higher performance. Service parts require production date verification - high-pressure fuel pumps before 08/2020 are incompatible with later units due to internal design changes (Mercedes AMG TB 07.0128).
The M257.930's primary reliability risk is high-pressure fuel pump failure on early builds, with elevated incidence in mixed driving conditions. Internal Mercedes quality reports from 2019 indicated a notable portion of pre-2020 engines required pump replacement before 150,000 km, while VCA data shows a share of emissions failures linked to lean misfires from degraded fuel delivery. Use of low-quality fuel and extended service intervals increase pump stress, making fuel quality and adherence to MB 229.52 specification critical.
Analysis derived from Mercedes-Benz technical bulletins (2017-2023) and UK DVSA failure statistics (2019-2024). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about MERCEDES-BENZ M257930.
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