The Mercedes-Benz CLS 400d 4MATIC, produced from June 2020 to April 2021, represents a compelling blend of performance and efficiency within the C257 CLS coupe generation. Positioned as a mid-to-high range offering, it catered to buyers seeking a luxurious four-door coupe experience with strong diesel power and all-wheel drive capability. This variant utilized Mercedes-Benz’s advanced OM 656 engine family, paired with the 9G-TRONIC automatic transmission, and formed a significant part of the CLS lineup during its brief production run. It was designed to appeal to customers prioritizing refined driving dynamics and long-distance comfort over outright sportiness, while still delivering impressive acceleration.
Technical Specifications
| Brand | Mercedes-Benz |
| Model | CLS |
| Generation | CLS coupe (C257) |
| Type | CLS 400d (330 Hp) 4MATIC 9G-TRONIC |
| Start of production | June, 2020 |
| End of production | April, 2021 |
| Powertrain Architecture | Internal Combustion engine |
| Body type | Coupe |
| Seats | 5 |
| Doors | 4 |
| Combined fuel consumption (WLTP) | 7.3 l/100 km (32.2 US mpg, 38.7 UK mpg, 13.7 km/l) |
| Fuel consumption (economy) – urban (NEDC) | 8.2-8.4 l/100 km (28.7 – 28 US mpg, 34.4 – 33.6 UK mpg, 12.2 – 11.9 km/l) |
| Fuel consumption (economy) – extra urban (NEDC) | 5-5.3 l/100 km (47 – 44.4 US mpg, 56.5 – 53.3 UK mpg, 20 – 18.9 km/l) |
| Fuel consumption (economy) – combined (NEDC) | 6.2-6.4 l/100 km (37.9 – 36.8 US mpg, 45.6 – 44.1 UK mpg, 16.1 – 15.6 km/l) |
| CO2 emissions (NEDC) | 162-169 g/km |
| Fuel Type | Diesel |
| Acceleration 0 – 100 km/h | 5 sec |
| Acceleration 0 – 62 mph | 5 sec |
| Acceleration 0 – 60 mph | 4.8 sec |
| Maximum speed | 250 km/h (155.34 mph), Electronically limited |
| Emission standard | Euro 6d-ISC-FCM |
| Weight-to-power ratio | 5.6 kg/Hp, 177.4 Hp/tonne |
| Weight-to-torque ratio | 2.7 kg/Nm, 376.3 Nm/tonne |
| Power | 330 Hp @ 3600-4200 rpm |
| Torque | 700 Nm @ 1200-3200 rpm (516.29 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 |
| Cylinder Bore | 82 mm (3.23 in.) |
| Piston Stroke | 92.3 mm (3.63 in.) |
| Compression ratio | 15.5:1 |
| Number of valves per cylinder | 4 |
| Fuel injection system | Diesel Commonrail |
| Engine aspiration | BiTurbo, Intercooler |
| Valvetrain | DOHC, CAMTRONIC |
| Engine oil capacity | 7.5 l (7.93 US qt | 6.6 UK qt) |
| Coolant | 13 l (13.74 US qt | 11.44 UK qt) |
| Kerb Weight | 1860-1873 kg (4100.6 – 4129.26 lbs.) |
| Max. weight | 2545-2558 kg (5610.76 – 5639.42 lbs.) |
| Max load | 685 kg (1510.17 lbs.) |
| Trunk (boot) space – minimum | 520 l (18.36 cu. ft.) |
| Fuel tank capacity | 50 l (13.21 US gal | 11 UK gal) |
| AdBlue tank | 23.5 l (6.21 US gal | 5.17 UK gal) |
| Max. roof load | 75 kg (165.35 lbs.) |
| Permitted trailer load with brakes (12%) | 1900 kg (4188.78 lbs.) |
| Permitted trailer load without brakes | 750 kg (1653.47 lbs.) |
| Permitted towbar download | 76 kg (167.55 lbs.) |
| Length | 4988 mm (196.38 in.) |
| Width | 1890 mm (74.41 in.) |
| Width including mirrors | 2069 mm (81.46 in.) |
| Height | 1435 mm (56.5 in.) |
| Wheelbase | 2939 mm (115.71 in.) |
| Front track | 1618-1619 mm (63.7 – 63.74 in.) |
| Rear (Back) track | 1620-1634 mm (63.78 – 64.33 in.) |
| Front overhang | 888 mm (34.96 in.) |
| Rear overhang | 1161 mm (45.71 in.) |
| Minimum turning circle (turning diameter) | 11.9 m (39.04 ft.) |
| Front brakes | Ventilated discs |
| Rear brakes | Ventilated discs |
| Number of gears and type of gearbox | 9 gears, automatic transmission G-TRONIC |
Powertrain & Engine Architecture
The CLS 400d 4MATIC is powered by the OM 656 2.9-liter inline-six cylinder diesel engine. This engine is a significant departure from the previous V6 diesel offerings, utilizing a modular design with a cylinder head featuring stepped combustion bowls and a two-stage turbocharging system. The two turbochargers – one large, low-pressure unit and one smaller, high-pressure unit – work in tandem to deliver both strong low-end torque and high-end power. The engine employs a common-rail direct injection system operating at pressures up to 2,700 bar, optimizing fuel atomization and combustion efficiency. The 9G-TRONIC nine-speed automatic transmission is standard, offering smooth and efficient gear changes. This transmission is known for its wide gear ratio spread, contributing to both fuel economy and responsive acceleration. The 4MATIC all-wheel-drive system provides enhanced traction and stability, distributing torque between the front and rear axles as needed.
Driving Characteristics
The CLS 400d 4MATIC delivers a refined and effortless driving experience. The engine’s substantial 700 Nm (516 lb-ft) of torque, available from a low 1200 rpm, provides strong acceleration in virtually any gear. The 0-60 mph sprint takes approximately 4.8 seconds, making it a surprisingly quick coupe. The 9G-TRONIC transmission contributes to smooth transitions between gears, and the all-wheel-drive system inspires confidence in various weather conditions. Compared to the CLS 350d, the 400d offers a noticeable increase in power and torque, resulting in more responsive acceleration. While not as overtly sporty as some of its competitors, the CLS 400d prioritizes comfort and refinement, making it an excellent grand tourer. The gear ratios are tuned for both fuel efficiency and quick response, with lower gears providing strong off-the-line acceleration and higher gears optimizing highway cruising.
Equipment & Trim Levels
The CLS 400d 4MATIC typically came well-equipped as standard. Features included leather upholstery, heated front seats, a premium sound system, a large infotainment display with Mercedes-Benz’s MBUX system, and a comprehensive suite of safety features such as automatic emergency braking, lane-keeping assist, and adaptive cruise control. Optional extras included air suspension, a panoramic sunroof, upgraded interior trim materials (wood, carbon fiber, or aluminum), and a head-up display. The interior design emphasized luxury and technology, with a flowing dashboard layout and ambient lighting. Trim levels were often differentiated by the availability of these optional packages and the choice of exterior colors and wheel designs.
Chassis & Braking
The CLS 400d 4MATIC utilizes a sophisticated chassis design focused on balancing comfort and handling. The front suspension features a multi-link setup with coil springs, while the rear suspension employs a multi-link independent suspension. Air suspension was available as an option, further enhancing ride comfort and allowing for adjustable ride height. Braking duties are handled by ventilated discs on all four wheels, providing ample stopping power. The electronic stability program (ESP) and anti-lock braking system (ABS) are standard, enhancing safety and control. Steering is rack-and-pinion with electric power assistance, offering precise and responsive steering feel.
Market Reception & Comparison
The CLS 400d 4MATIC was generally well-received by automotive critics. It was praised for its powerful and efficient engine, comfortable ride, and luxurious interior. Compared to other diesel-powered coupes in its class, such as the BMW 8 Series and Audi A7, the CLS 400d offered a compelling combination of performance, refinement, and technology. Fuel economy was a strong point, with the CLS 400d achieving around 32.2 US mpg in combined driving. Reliability reports have been generally positive, although, as with any complex vehicle, preventative maintenance is crucial. Some reviewers noted that the CLS’s styling was polarizing, but its overall quality and driving experience were highly regarded.
Legacy
The OM 656 engine family, as featured in the CLS 400d, has proven to be a robust and reliable powerplant. The 9G-TRONIC transmission has also demonstrated good long-term durability. On the used car market, the CLS 400d 4MATIC holds its value relatively well, due to its desirable combination of performance, luxury, and fuel efficiency. However, potential buyers should be mindful of regular maintenance requirements, particularly regarding the diesel particulate filter and AdBlue system. The CLS 400d represents a high point in Mercedes-Benz’s diesel coupe offerings, showcasing the brand’s commitment to both performance and efficiency.
