Technical Specifications
| Brand | Mercedes-Benz |
| Model | CLS |
| Generation | CLS coupe (C257) |
| Type | CLS 400d (340 Hp) 4MATIC 9G-TRONIC |
| Start of production | March, 2018 |
| End of production | June, 2020 |
| Powertrain Architecture | Internal Combustion engine |
| Body type | Coupe |
| Seats | 5 |
| Doors | 4 |
| Combined fuel consumption (WLTP) | 6.8-7.5 l/100 km (34.6 – 31.4 US mpg, 41.5 – 37.7 UK mpg, 14.7 – 13.3 km/l) |
| CO2 emissions (WLTP) | 178-197 g/km |
| Fuel consumption (economy) – urban (NEDC) | 6.8-7.1 l/100 km (34.6 – 33.1 US mpg, 41.5 – 39.8 UK mpg, 14.7 – 14.1 km/l) |
| Fuel consumption (economy) – extra urban (NEDC) | 5.1-5.4 l/100 km (46.1 – 43.6 US mpg, 55.4 – 52.3 UK mpg, 19.6 – 18.5 km/l) |
| Fuel consumption (economy) – combined (NEDC) | 5.8-6 l/100 km (40.6 – 39.2 US mpg, 48.7 – 47.1 UK mpg, 17.2 – 16.7 km/l) |
| CO2 emissions (NEDC) | 152-159 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-TEMP-EVAP-ISC |
| Weight-to-power ratio | 5.5 kg/Hp, 182.8 Hp/tonne |
| Weight-to-torque ratio | 2.7 kg/Nm, 376.3 Nm/tonne |
| Power | 340 Hp @ 4400 rpm |
| Power per litre | 116.2 Hp/l |
| 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 | 8.5 l (8.98 US qt | 7.48 UK qt) |
| Coolant | 13 l (13.74 US qt | 11.44 UK qt) |
| Kerb Weight | 1860-1869 kg (4100.6 – 4120.44 lbs.) |
| Max. weight | 2545-2554 kg (5610.76 – 5630.61 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.) |
| Drag coefficient (Cd) | 0.26 |
| Minimum turning circle (turning diameter) | 11.9 m (39.04 ft.) |
| Approach angle | 13.4° |
| Departure angle | 12.2° |
| Ramp-over (brakeover) angle | 8.6° |
| 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 suspension | Coil spring, Independent multi-link suspension, Transverse stabilizer, Air Suspension – Optional |
| Rear suspension | Independent multi-link spring suspension with stabilizer, Air Suspension – Optional |
| Front brakes | Ventilated discs |
| Rear brakes | Ventilated discs |
The Mercedes-Benz CLS 400d 4MATIC, part of the C257 series produced from 2018 to 2020, represents a significant evolution of the four-door coupe concept. Building upon the success of its predecessors, the C257 CLS aimed to deliver a more refined and technologically advanced experience. The 400d variant, powered by a potent inline-six diesel engine, occupied a sweet spot in the lineup, offering a compelling combination of performance, efficiency, and luxury. It was designed to appeal to drivers who desired a stylish and comfortable grand tourer without sacrificing the practicality of a four-door configuration. The CLS 400d 4MATIC was a key player in Mercedes-Benz’s strategy to maintain a strong presence in the premium coupe market.
Powertrain & Engine Architecture
At the heart of the CLS 400d 4MATIC lies the OM 656 2.9-liter inline-six diesel engine. This engine, a cornerstone of Mercedes-Benz’s modern diesel lineup, is renowned for its smooth operation, high efficiency, and impressive torque output. The OM 656 utilizes a sophisticated common-rail direct injection system, delivering fuel at pressures up to 2,700 bar for optimized combustion. A bi-turbocharger setup, employing a variable geometry turbine (VGT) and a conventional turbocharger, provides both rapid response and sustained power delivery. The engine also features CAMTRONIC valve lift adjustment, allowing for optimized engine performance and reduced emissions. Paired with the engine is the 9G-TRONIC nine-speed automatic transmission. This transmission is known for its smooth and quick shifts, contributing to both performance and fuel efficiency. The 9G-TRONIC features a wide gear ratio spread, allowing the engine to operate in its optimal efficiency range more frequently.
Driving Characteristics
The CLS 400d 4MATIC delivers a refined and effortless driving experience. The 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 is dispatched in around 4.8 seconds, making it a surprisingly quick vehicle for its size and weight. The 9G-TRONIC transmission contributes to this performance with seamless gear changes, minimizing interruption to the power delivery. Compared to the lower-powered CLS 350d, the 400d offers a noticeable increase in performance, particularly in overtaking situations. While not as overtly sporty as the AMG variants, the 400d provides ample power for confident and comfortable cruising. The 4MATIC all-wheel-drive system ensures excellent traction in all weather conditions, enhancing stability and control. The gear ratios are tuned for a balance between acceleration and fuel economy, with higher gears designed for relaxed highway cruising.
Equipment & Trim Levels
The CLS 400d 4MATIC came standard with a comprehensive array of luxury features. Interior appointments typically included high-quality leather upholstery, wood trim, and ambient lighting. Standard technology included the Mercedes-Benz User Experience (MBUX) infotainment system with a large touchscreen display, smartphone integration (Apple CarPlay and Android Auto), and a premium sound system. Safety features were also abundant, including adaptive cruise control, lane keeping assist, automatic emergency braking, and blind spot monitoring. Optional extras included a panoramic sunroof, upgraded leather packages, a head-up display, and advanced driver assistance systems. The overall interior design emphasized a modern and sophisticated aesthetic, with a focus on comfort and convenience.
Chassis & Braking
The CLS 400d 4MATIC features a sophisticated chassis designed to balance comfort and handling. The front suspension utilizes a multi-link setup with coil springs, while the rear suspension employs an independent multi-link design as well. Air suspension was available as an option, further enhancing ride comfort and allowing for adjustable ride height. The braking system consists of ventilated discs on all four wheels, providing ample stopping power. Anti-lock braking system (ABS), electronic stability control (ESC), and traction control are standard features, enhancing safety and control. The 4MATIC all-wheel-drive system distributes power between the front and rear axles as needed, optimizing traction and stability. Stabilizer bars are fitted to both the front and rear axles to minimize body roll during cornering.
Market Reception & Comparison
The CLS 400d 4MATIC was generally well-received by automotive critics. It was praised for its refined driving experience, powerful engine, and luxurious interior. The diesel engine was particularly lauded for its smoothness and efficiency. Compared to the CLS 350d, the 400d offered a significant performance upgrade without a substantial increase in fuel consumption. Against the gasoline-powered CLS 53 AMG, the 400d provided a more fuel-efficient alternative, albeit with slightly less outright performance. Fuel economy figures typically ranged from 34.6 to 31.4 US mpg, making it a relatively economical option for a vehicle of its size and performance. Reliability reports have generally been positive, with the OM 656 engine proving to be a robust and dependable unit.
Legacy
The CLS 400d 4MATIC represents a high point in Mercedes-Benz’s diesel technology. The OM 656 engine has established itself as a reliable and efficient powerplant, and the C257 CLS continues to be a desirable vehicle in the used car market. The combination of performance, luxury, and fuel economy makes it an attractive option for buyers seeking a sophisticated grand tourer. While diesel engines have faced increasing scrutiny in recent years, the CLS 400d 4MATIC remains a testament to the potential of modern diesel technology. Its robust construction and well-engineered powertrain suggest that it will continue to provide years of reliable service for its owners.
