Mercedes-Benz Engine Types and Versions Overview

Mercedes-Benz employs a diverse range of engine families, each designated by a modular code (e.g., M 256, OM 654). These engines span gasoline, diesel, hybrid, and fully electric drive systems, tailored for different vehicle classes and performance levels. The lineup has evolved towards downsizing, turbocharging, and electrification.

1. Current Gasoline Engines (Modular Family)

Modern, efficient engines featuring turbocharging and often integrated electrification.

• M 139 (2.0L I4): The world's most powerful series-production four-cylinder. Used in the Mercedes-AMG 45 models (A 45 S, CLA 45 S), producing up to 421 hp.
• M 254 (2.0L I4 & 3.0L I6): The latest modular engine with integrated starter-generator (ISG) for mild-hybrid functionality. Replaces the M 264. Used in C-Class, E-Class, and GLC.
• M 256 (3.0L Inline-6): A flagship gasoline engine with an integrated ISG (EQ Boost). Features a 48-volt electrical system for electric compressor (eliminates turbo lag) and smooth start-stop. Powers S-Class, GLE, CLS, and AMG 53 models.
• M 176/M 177/M 178 (4.0L V8 Bi-Turbo): The AMG V8 family. M 176 is the standard version, M 177 is the high-performance AMG version (in C 63, E 63), and M 178 is the dry-sump version for sports cars like the AMG GT.

2. Current Diesel Engines

Efficient and torque-rich engines, primarily for SUVs and executive sedans.

• OM 654 (2.0L I4 Diesel): The modular diesel engine, widely used in C-Class, E-Class, and GLC/GLE. Features a stepped-bowl combustion process for efficiency and reduced emissions.
• OM 656 (3.0L Inline-6 Diesel): The premium diesel engine, succeeding the OM 642. Used in S-Class, GLE, and GLS. Also employs a 48-volt system (in some versions) for an electric auxiliary compressor.

3. Plug-in Hybrid Electric Vehicle (PHEV) Powertrains

Combining internal combustion engines with powerful electric motors and large batteries.

• Gasoline PHEVs: Typically pair a 2.0L M 254 or 3.0L M 256 engine with an electric motor integrated into the transmission. Examples include the C 300 e, GLE 550 e, and S 580 e. Offer significant electric-only range (approx. 50-100 km).
• Diesel PHEV: The E 300 de combines the OM 654 diesel engine with an electric motor, focusing on long-distance efficiency with local electric driving capability.
• AMG Performance PHEVs: High-performance hybrids like the C 63 S E PERFORMANCE and GT 63 S E PERFORMANCE. They use a modified 2.0L or 4.0L V8 engine paired with a powerful electric motor on the rear axle and a high-performance battery derived from Formula 1.

4. Electric Drive Units (EQ Models)

Dedicated electric vehicle architecture with no internal combustion engine.

• EVA Platform Motors: Used in EQS, EQE, EQS SUV, and EQE SUV. Features one or two permanently excited synchronous motors (PSM). The top versions (like EQS 580 4MATIC) use dual motors for all-wheel drive.
• MMA Platform Motors: For upcoming compact electric models. Will feature new-generation electric motors and silicon carbide inverters for greater efficiency.

5. Historic & Notable Engine Families

Iconic engines that defined past generations.

• M 104 (3.2L I6): A renowned inline-six from the 1990s, known for its smoothness and durability.
• M 113/M 155 (5.4L V8 & 6.2L V8): The naturally aspirated V8 era. M 113 was supercharged in AMG 55 models. The M 156 (6.2L V8) was AMG's first in-house engine, legendary for its sound and character.
• OM 606 (3.0L I6 Diesel): A legendary turbo-diesel known for its extreme reliability and tunability.

Mercedes-Benz Engine Family Reference Table

Engine Code	Type & Displacement	Key Technology	Typical Applications
M 139	2.0L Turbo I4 (Gasoline)	High-pressure turbo, reverse flow head	AMG 45 Series (A 45, CLA 45)
M 256	3.0L Turbo I6 (Gasoline)	Integrated 48V ISG (EQ Boost), Electric Compressor	S-Class, GLE, CLS, AMG 53 Models
M 177	4.0L Bi-Turbo V8 (Gasoline)	Hot-V turbo configuration, AMG-specific	AMG 63 Models (C 63, E 63, G 63)
OM 654	2.0L Turbo I4 (Diesel)	Modular design, stepped-bowl combustion	C 220 d, E 220 d, GLC 220 d
OM 656	3.0L Turbo I6 (Diesel)	48V system (on some), aluminum block	S 350 d, GLE 350 d
PHEV Systems	Combustion Engine + e-Motor	Large battery (e.g., 25.4 kWh), integrated motor	C 300 e, GLE 550 e, S 580 e
EQ Electric Drive	Permanent Magnet Synchronous Motor	Dedicated EV platform, multiple power levels	EQS, EQE, EQS SUV

Conclusion: Mercedes-Benz's engine strategy showcases a transition from traditional combustion to electrification. The current portfolio is dominated by modular, turbocharged gasoline (M 254, M 256) and diesel (OM 654, OM 656) engines, almost universally enhanced by 48-volt mild-hybrid technology. High-performance is delivered by the handcrafted AMG V8 (M 177/178) and the groundbreaking four-cylinder M 139. The future is clearly electrified, with sophisticated PHEV systems bridging the gap and dedicated EQ electric drive units leading the charge towards a fully electric lineup.