The Mercedes-Benz CLS 350d 4MATIC, produced from 2018 to 2021 as part of the C257 generation CLS, represented a compelling blend of luxury, performance, and efficiency within the four-door coupe segment. Positioned as a mid-range offering in the CLS lineup, it slotted between the entry-level CLS 300d and the higher-performance CLS 450, offering a significant step up in power and torque while maintaining a focus on fuel economy thanks to its advanced diesel powertrain. This variant was primarily marketed towards buyers seeking a sophisticated grand tourer with all-weather capability provided by Mercedes-Benz’s 4MATIC all-wheel-drive system.
Technical Specifications
| Brand | Mercedes-Benz |
| Model | CLS |
| Generation | CLS coupe (C257) |
| Type | CLS 350d (286 Hp) 4MATIC 9G-TRONIC |
| Start of production | 2018 |
| End of production | 2021 |
| Powertrain Architecture | Internal Combustion engine |
| Body type | Coupe |
| Seats | 5 |
| Doors | 4 |
| Fuel consumption at Low speed (WLTP) | 6.8 l/100 km (34.6 US mpg, 41.5 UK mpg, 14.7 km/l) |
| Fuel consumption at very high speed (WLTP) | 7.5 l/100 km (31.4 US mpg, 37.7 UK mpg, 13.3 km/l) |
| CO2 emissions (WLTP) | 178-197 g/km |
| Fuel consumption (economy) – urban | 6.5-6.8 l/100 km (36.2 – 34.6 US mpg, 43.5 – 41.5 UK mpg, 15.4 – 14.7 km/l) |
| Fuel consumption (economy) – extra urban | 4.9-5.2 l/100 km (48 – 45.2 US mpg, 57.6 – 54.3 UK mpg, 20.4 – 19.2 km/l) |
| Fuel consumption (economy) – combined | 5.6-5.8 l/100 km (42 – 40.6 US mpg, 50.4 – 48.7 UK mpg, 17.9 – 17.2 km/l) |
| CO2 emissions | 148-156 g/km |
| Fuel Type | Diesel |
| Acceleration 0 – 100 km/h | 5.7 sec |
| Acceleration 0 – 62 mph | 5.7 sec |
| Acceleration 0 – 60 mph | 5.4 sec |
| Maximum speed | 250 km/h (155.34 mph) |
| Emission standard | Euro 6 |
| Weight-to-power ratio | 6.5 kg/Hp, 153.8 Hp/tonne |
| Weight-to-torque ratio | 3.1 kg/Nm, 322.6 Nm/tonne |
| Power | 286 Hp |
| Power per litre | 97.8 Hp/l |
| Torque | 600 Nm @ 1200-3200 rpm (442.54 lb.-ft. @ 1200-3200 rpm) |
| Engine layout | Front, Longitudinal |
| Engine Model/Code | OM 656.929 |
| Engine displacement | 2925 cm3 (178.49 cu. in.) |
| Number of cylinders | 6 |
| Engine configuration | Inline |
| Number of valves per cylinder | 4 |
| Fuel injection system | Diesel Commonrail |
| Engine aspiration | Turbocharger, Intercooler |
| Engine oil capacity | 8 l (8.45 US qt | 7.04 UK qt) |
| Coolant | 13 l (13.74 US qt | 11.44 UK qt) |
| Kerb Weight | 1860 kg (4100.6 lbs.) |
| Max. weight | 2545 kg (5610.76 lbs.) |
| Max load | 685 kg (1510.17 lbs.) |
| Fuel tank capacity | 50 l (13.21 US gal | 11 UK gal) |
| Permitted trailer load with brakes (12%) | 1900 kg (4188.78 lbs.) |
| Permitted trailer load without brakes | 750 kg (1653.47 lbs.) |
| Length | 4988 mm (196.38 in.) |
| Width | 1890 mm (74.41 in.) |
| Height | 1435 mm (56.5 in.) |
| Wheelbase | 2939 mm (115.71 in.) |
| Front track | 1618 mm (63.7 in.) |
| Front overhang | 888 mm (34.96 in.) |
| Rear overhang | 1161 mm (45.71 in.) |
| Ride height (ground clearance) | 93 mm (3.66 in.) |
| Drag coefficient (Cd) | 0.26 |
| Approach angle | 13.4° |
| Departure angle | 12.2° |
| Drivetrain Architecture | The Internal combustion engine (ICE) drives permanently the four wheels of the vehicle. |
| Drive wheel | All wheel drive (4×4) |
| Number of gears and type of gearbox | 9 gears, automatic transmission G-TRONIC |
| Front brakes | Ventilated discs |
| Rear brakes | Ventilated discs |
INTRODUCTION
The C257 CLS 350d 4MATIC, launched in 2018, built upon the success of its predecessors by offering a more refined and technologically advanced package. It represented the third generation of the CLS, which pioneered the four-door coupe segment. The C257 moved to the MRA (Modular Rear-wheel-drive Architecture) platform, shared with the E-Class and S-Class, allowing for greater flexibility in design and engineering. The 350d variant, with its potent diesel engine and standard 4MATIC all-wheel drive, aimed to provide a comfortable and capable grand touring experience, particularly appealing to European markets where diesel engines remained popular.
Powertrain & Engine Architecture
At the heart of the CLS 350d 4MATIC lies the OM 656.929, a 2.9-liter inline-six cylinder diesel engine. This engine marked a significant departure from the previous V6 diesel offerings, utilizing a modular design and advanced technologies. The OM 656 features a stepped combustion process, where the combustion is initiated in two stages to reduce noise and emissions. It employs a two-stage turbocharging system with a variable turbine geometry (VTG) turbocharger and an additional smaller turbocharger, providing both strong low-end torque and high-end power. Fuel is delivered via a common rail direct injection system operating at extremely high pressures (2700 bar) for optimized combustion. The engine is paired with Mercedes-Benz’s 9G-TRONIC nine-speed automatic transmission. This transmission is known for its smooth shifts and wide gear ratio spread, contributing to both fuel efficiency and responsive acceleration. The 9G-TRONIC features a torque converter lockup clutch that engages across multiple gears, further enhancing efficiency.
Driving Characteristics
The CLS 350d 4MATIC delivers a refined and effortless driving experience. The 600 Nm (442.54 lb-ft) of torque, available from a low 1200 rpm, provides strong acceleration in virtually any gear. The 9G-TRONIC transmission is well-tuned, offering seamless gear changes and keeping the engine within its optimal power band. While not as overtly sporty as the CLS 450, the 350d offers more than adequate performance for highway cruising and spirited driving. The 4MATIC all-wheel-drive system provides excellent traction in all weather conditions, enhancing stability and confidence. The gear ratios are optimized for both fuel economy and responsiveness, with a relatively tall final drive contributing to lower engine speeds at highway speeds. Compared to the CLS 300d, the 350d offers a noticeable increase in power and torque, resulting in quicker acceleration and more relaxed cruising. It doesn’t possess the outright performance of the CLS 450, but provides a more balanced and economical alternative.
Equipment & Trim Levels
The CLS 350d 4MATIC came standard with a generous array of features, reflecting its positioning as a luxury vehicle. Standard equipment typically included leather upholstery, automatic climate control, a high-resolution infotainment system with navigation, and a suite of driver-assistance systems such as adaptive cruise control, lane-keeping assist, and automatic emergency braking. Optional extras included a premium Burmester surround sound system, a panoramic sunroof, ventilated and massaging front seats, and a head-up display. Interior trim options ranged from wood veneers to aluminum accents, allowing buyers to personalize the cabin to their preferences. The dashboard layout was characterized by a sleek, minimalist design with dual 12.3-inch displays integrated under a single glass cover, creating a modern and sophisticated aesthetic.
Chassis & Braking
The C257 CLS 350d 4MATIC utilizes a four-link front suspension and a multi-link rear suspension, providing a comfortable and controlled ride. The suspension is tuned to prioritize comfort, but still offers good body control in corners. The 4MATIC all-wheel-drive system employs a multi-plate clutch to distribute torque between the front and rear axles, adapting to changing road conditions. Braking duties are handled by ventilated discs on all four wheels, providing ample stopping power. The CLS 350d typically featured slightly smaller rear brake rotors compared to the higher-performance CLS 450. Standard safety features included ABS, electronic stability control, and a tire pressure monitoring system.
Market Reception & Comparison
The CLS 350d 4MATIC was generally well-received by automotive critics. It was praised for its refined engine, comfortable ride, and luxurious interior. The fuel economy was also a strong point, particularly compared to gasoline-powered alternatives. Some critics noted that the steering lacked a bit of feel, and that the car’s size could make it challenging to maneuver in tight spaces. Compared to the CLS 300d, the 350d offered a significant performance upgrade without a substantial increase in fuel consumption. Against the CLS 450, it provided a more economical option, albeit with slightly less power and performance. In the European market, the 350d was a popular choice due to its combination of performance, efficiency, and practicality.
Legacy
The OM 656 engine family, as featured in the CLS 350d 4MATIC, has proven to be a robust and reliable powertrain. While long-term reliability data is still accumulating, early indications suggest that the engine is durable and capable of high mileage. The 9G-TRONIC transmission has also demonstrated good reliability. On the used car market, the C257 CLS 350d 4MATIC represents a compelling value proposition, offering a luxurious and capable grand tourer at a more affordable price point than newer models. Its combination of performance, efficiency, and all-weather capability continues to appeal to buyers seeking a sophisticated and practical coupe.
