2020-2023 Mercedes-Benz S-class Long (V223) S 400d (330 Hp) 4MATIC 9G-TRONIC

The Mercedes-Benz S-Class Long (V223) S 400d 4MATIC, produced from 2020 to April 2023, represents a significant iteration of the flagship S-Class sedan. This variant, distinguished by its extended wheelbase (“Long” designation) and powerful diesel engine, was primarily aimed at markets where rear passenger space and refined long-distance cruising were highly valued. It slots into the S-Class range as a performance-oriented diesel option, positioned between the entry-level S 350d and the higher-performance S 500d or petrol-powered S 580 models. The V223 generation marked a substantial leap forward in technology, interior luxury, and driver assistance systems, continuing the S-Class’s tradition of innovation.

Technical Specifications

INTRODUCTION

The S 400d 4MATIC, introduced in 2020 as part of the V223 S-Class generation, represents Mercedes-Benz’s commitment to diesel power within its flagship luxury sedan. The V223 S-Class, built on the updated M256 platform, prioritized technological advancement and passenger comfort. The “Long” wheelbase version, adding approximately 10cm (3.9 inches) to the standard S-Class, specifically caters to buyers seeking enhanced rear legroom, a common preference in markets like China and increasingly, the United States. This variant aimed to deliver a blend of performance, efficiency, and the opulent experience synonymous with the S-Class nameplate.

Powertrain & Engine Architecture

At the heart of the S 400d 4MATIC lies the OM 656.929, a 2.9-liter inline-six cylinder diesel engine. This engine is a cornerstone of Mercedes-Benz’s modern diesel strategy, known for its refined operation and impressive torque output. The OM 656 utilizes a sophisticated diesel commonrail fuel injection system, delivering fuel at extremely high pressures for optimized combustion. A bi-turbocharger setup, employing both a conventional and an exhaust gas turbocharger, provides a broad torque curve and minimizes turbo lag. The engine also features a variable valve timing system (DOHC) and an intercooler to further enhance performance and efficiency. Paired with the engine is the 9G-TRONIC nine-speed automatic transmission, renowned for its smooth shifts and wide gear ratios. This transmission is specifically tuned to complement the engine’s torque characteristics, providing effortless acceleration and relaxed highway cruising.

Driving Characteristics

The S 400d 4MATIC delivers a driving experience characterized by effortless power and refinement. The 700 Nm (516 lb-ft) of torque, available from a low 1200 rpm, provides strong acceleration in virtually any gear. While not as overtly sporty as some of its petrol-powered siblings, the S 400d offers a 0-60 mph time of around 5.1 seconds, which is more than adequate for most driving situations. The 9G-TRONIC transmission contributes to a smooth and seamless driving experience, with well-spaced gear ratios that keep the engine in its optimal power band. The 4MATIC all-wheel-drive system provides excellent traction and stability, particularly in adverse weather conditions. Compared to the S 350d, the S 400d offers a noticeable performance upgrade, while remaining more fuel-efficient than the higher-output S 500d.

Equipment & Trim Levels

The S 400d 4MATIC, being a flagship model, came standard with a comprehensive array of luxury features. These included leather upholstery, heated and ventilated front and rear seats, a Burmester surround sound system, and a large dual-screen display incorporating the MBUX infotainment system. Standard safety features included adaptive cruise control, lane keeping assist, automatic emergency braking, and a 360-degree camera system. Optional extras included a head-up display, massaging seats, a rear-seat entertainment system, and various interior trim options. The extended wheelbase provided significantly more rear legroom, making it a popular choice for chauffeured transport.

Chassis & Braking

The V223 S-Class features an advanced chassis design focused on ride comfort and handling. The S 400d 4MATIC utilizes an independent multi-link suspension system at both the front and rear, coupled with Mercedes-Benz’s AIRMATIC air suspension. This system automatically adjusts the suspension damping and ride height to optimize comfort and stability. The car is equipped with ventilated disc brakes on all four wheels, providing ample stopping power. Additional safety features include ABS (Anti-lock Braking System) and 4-wheel steering (4WS), which enhances maneuverability at low speeds and stability at high speeds.

Market Reception & Comparison

The S 400d 4MATIC was generally well-received by automotive critics. It was praised for its refined engine, comfortable ride, and luxurious interior. The diesel engine’s fuel efficiency was also a significant selling point, particularly in Europe. Compared to the S 350d, the S 400d offered a noticeable performance improvement without sacrificing fuel economy. Against the petrol-powered S 500d, the S 400d provided a more balanced combination of performance and efficiency, appealing to buyers who prioritized long-distance comfort and fuel savings. However, the diesel variant faced increasing scrutiny due to tightening emissions regulations in some markets.

Legacy

The OM 656 engine family, including the version found in the S 400d 4MATIC, has proven to be remarkably reliable. While diesel engines generally require diligent maintenance, the OM 656 has demonstrated a robust design and long service life. On the used car market, the V223 S 400d 4MATIC holds its value well, particularly examples with low mileage and a comprehensive service history. The combination of luxury, performance, and efficiency continues to make it an attractive option for buyers seeking a high-end luxury sedan. The V223 S-Class, and the S 400d variant specifically, represents a high point in modern luxury car engineering, blending cutting-edge technology with traditional Mercedes-Benz values.