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 V22…
All production years 2017–2023 meet Euro 6d emissions standards .
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 | Refer to vehicle handbook / manufacturer specification | |
Dry weight | 209 kg |
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.
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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 manufacturer technical service bulletins and industry workshop records. Repair procedures should follow manufacturer guidelines.
The most common questions about engine codes, what they mean, how to find them and how this database works
The M257.930 delivers exceptional performance but early models (2017-2019) are prone to high-pressure fuel pump failure. Later revisions (post-2020) with upgraded components significantly improve durability. Regular maintenance, strict use of 0W-40 MB 229.52 oil, and use of premium fuel are essential for long-term reliability.
Key issues include high-pressure fuel pump wear (especially pre-2020), coolant leaks from the electric water pump, ignition coil failures under high load, and turbocharger oil seal wear. These are documented in Mercedes technical bulletins and are manageable with preventative maintenance and proper fuel quality.
This 3.0L turbocharged inline-six was used in flagship models: the W222 S-Class (S 560, S 560 L), W223 S-Class (S 500, S 500 L), and V222 S-Class Long (S 560 L) from 2017 to 2023. It replaced the naturally aspirated M276 engine and is part of Mercedes-Benz's electrified M256/M257 engine family.
Aftermarket ECU tuning is common on the M257930 platform, but increasing boost or altering engine parameters accelerates component wear, impacts emissions compliance, and may void vehicle warranties. Any modifications should be evaluated carefully by a qualified specialist.
Fuel consumption is moderate for a performance luxury sedan. In an S 500, expect ~11.0 L/100km (city) and ~7.5 L/100km (highway), or approximately 26–35 mpg UK. Real-world figures depend heavily on driving style, but the EQ Boost system helps improve efficiency during urban driving.
Yes. The M257 series is an interference engine. If the timing chain fails or jumps, pistons can collide with open valves, resulting in catastrophic internal damage. Regular inspection of the chain and tensioner is crucial to prevent expensive repairs.
Mercedes specifies 0W-40 oil meeting MB 229.52 specification. This high-performance synthetic oil is essential for maintaining oil pressure and protecting turbocharger bearings and piston components under high-RPM operation. Oil changes should be performed every 15,000 km or annually to ensure optimal lubrication and longevity.
Comprehensive technical documentation and regulatory references
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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)
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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.
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