The Mercedes-Benz C-Class Coupe (C205), particularly the C 300d variant with the 9G-TRONIC automatic transmission, represents a compelling blend of luxury, performance, and efficiency within the compact executive coupe segment. Introduced with the facelift in 2018 and continuing through 2021, this model aimed to deliver a more refined and dynamic driving experience compared to its sedan counterpart, while offering the practicality of a diesel powertrain. Positioned as a mid-to-upper trim level within the C-Class Coupe range, the C 300d catered to buyers seeking a balance between spirited performance and long-distance comfort.
Technical Specifications
| Brand | Mercedes-Benz |
| Model | C-class |
| Generation | C-class Coupe (C205, facelift 2018) |
| Type (Engine) | C 300d (245 Hp) 9G-TRONIC |
| Start of production | 2018 |
| End of production | 2021 |
| Powertrain Architecture | Internal Combustion engine |
| Body type | Coupe |
| Seats | 4 |
| Doors | 2 |
| Fuel consumption at Low speed (WLTP) | 5.4 l/100 km (43.6 US mpg, 52.3 UK mpg, 18.5 km/l) |
| Fuel consumption at very high speed (WLTP) | 6.3 l/100 km (37.3 US mpg, 44.8 UK mpg, 15.9 km/l) |
| CO2 emissions (WLTP) | 142-165 g/km |
| Fuel consumption (economy) – urban | 6.0-6.4 l/100 km (39.2 – 36.8 US mpg, 47.1 – 44.1 UK mpg, 16.7 – 15.6 km/l) |
| Fuel consumption (economy) – extra urban | 4.3-4.9 l/100 km (54.7 – 48 US mpg, 65.7 – 57.6 UK mpg, 23.3 – 20.4 km/l) |
| Fuel consumption (economy) – combined | 4.9-5.4 l/100 km (48 – 43.6 US mpg, 57.6 – 52.3 UK mpg, 20.4 – 18.5 km/l) |
| CO2 emissions | 129 – 143 g/km |
| Fuel Type | Diesel |
| Acceleration 0 – 100 km/h | 6 sec |
| Acceleration 0 – 62 mph | 6 sec |
| Acceleration 0 – 60 mph | 5.7 sec |
| Maximum speed | 250 km/h (155.34 mph) |
| Emission standard | Euro 6 |
| Weight-to-power ratio | 6.6 kg/Hp, 151.7 Hp/tonne |
| Weight-to-torque ratio | 3.2 kg/Nm, 309.6 Nm/tonne |
| Power | 245 Hp |
| Power per litre | 125.6 Hp/l |
| Torque | 500 Nm @ 1600-2400 rpm (368.78 lb.-ft. @ 1600-2400 rpm) |
| Engine layout | Front, Longitudinal |
| Engine Model/Code | OM 654.920 |
| Engine displacement | 1950 cm3 (119 cu. in.) |
| Number of cylinders | 4 |
| Engine configuration | Inline |
| Number of valves per cylinder | 4 |
| Fuel injection system | Diesel Commonrail |
| Engine aspiration | Turbocharger, Intercooler |
| Engine oil capacity | 6.8 l (7.19 US qt | 5.98 UK qt) |
| Coolant | 10 l (10.57 US qt | 8.8 UK qt) |
| Kerb Weight | 1615 kg (3560.47 lbs.) |
| Max. weight | 2185 kg (4817.1 lbs.) |
| Max load | 570 kg (1256.63 lbs.) |
| Fuel tank capacity | 50 l (13.21 US gal | 11 UK gal) |
| Permitted trailer load with brakes (12%) | 1800 kg (3968.32 lbs.) |
| Permitted trailer load without brakes | 750 kg (1653.47 lbs.) |
| Length | 4686 mm (184.49 in.) |
| Width | 1810 mm (71.26 in.) |
| Height | 1405 mm (55.31 in.) |
| Wheelbase | 2840 mm (111.81 in.) |
| Front track | 1567 mm (61.69 in.) |
| Front overhang | 790 mm (31.1 in.) |
| Rear overhang | 1056 mm (41.57 in.) |
| Ride height (ground clearance) | 88 mm (3.46 in.) |
| Approach angle | 13.2° |
| Departure angle | 14.3° |
| Drivetrain Architecture | The Internal combustion engine (ICE) drives the rear wheels of the vehicle. |
| Drive wheel | Rear wheel drive |
| Number of gears and type of gearbox | 9 gears, automatic transmission G-TRONIC |
| Front brakes | Ventilated discs |
| Rear brakes | Ventilated discs |
| Assisting systems | ABS (Anti-lock braking system) |
| Steering type | Steering rack and pinion |
| Power steering | Electric Steering |
INTRODUCTION
The C 205 C-Class Coupe, launched in 2015 and receiving a significant facelift in 2018, represented Mercedes-Benz’s attempt to create a more emotionally appealing and dynamically focused alternative to the C-Class sedan. The C 300d 9G-TRONIC, introduced with the facelift, was a key component of this strategy. Built on the MRA (Modular Rear-wheel Architecture) platform shared with other Mercedes-Benz models, the C-Class Coupe aimed to deliver a premium experience with a focus on style and driving pleasure. The C 300d specifically targeted buyers who desired the performance of a larger engine but with the fuel efficiency benefits of a modern diesel.
Powertrain & Engine Architecture
At the heart of the C 300d lies the OM 654.920, a 2.0-liter inline-four cylinder diesel engine. This engine is a cornerstone of Mercedes-Benz’s modern diesel lineup, known for its advanced technology and efficiency. The OM 654 features a steel piston, a variable-geometry turbocharger, and a sophisticated common-rail direct injection system operating at pressures up to 2,700 bar. This high-pressure injection ensures precise fuel atomization, leading to cleaner combustion and improved power delivery. The engine also incorporates a diesel particulate filter (DPF) to meet stringent Euro 6 emissions standards. The 9G-TRONIC nine-speed automatic transmission is paired with the engine, offering smooth and efficient gear changes. This transmission is known for its wide gear ratio spread, allowing for both relaxed cruising and responsive acceleration. The transmission’s programming is tailored to the characteristics of the diesel engine, optimizing for fuel economy and torque delivery.
Driving Characteristics
The C 300d 9G-TRONIC delivers a refined and comfortable driving experience. The 500 Nm (368 lb-ft) of torque, available from 1600-2400 rpm, provides strong acceleration in everyday driving situations. While not as overtly sporty as some of its gasoline-powered siblings, the C 300d offers a respectable 0-60 mph time of around 5.7 seconds. The 9G-TRONIC transmission contributes to this performance by keeping the engine within its optimal power band. The long gear ratios prioritize fuel efficiency during highway cruising, while the transmission can quickly downshift for overtaking maneuvers. Compared to the C 300 gasoline variant, the C 300d offers superior fuel economy and a more relaxed driving experience, but with slightly less outright acceleration. Compared to the C 220d, the C 300d provides a noticeable power upgrade, resulting in more confident performance, especially when fully loaded or tackling inclines.
Equipment & Trim Levels
The C 300d typically came well-equipped, reflecting its position as a mid-to-upper trim level. Standard features 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 and lane-keeping assist. Optional extras included a panoramic sunroof, premium sound system, and various interior trim options. The interior design emphasized luxury and modernity, with high-quality materials and a driver-focused layout. The coupe’s interior differed from the sedan with a more sculpted dashboard and sportier seats.
Chassis & Braking
The C-Class Coupe’s chassis is tuned for a balance of comfort and handling. The suspension utilizes a four-link front axle and a multi-link rear axle, providing a smooth and controlled ride. The C 300d typically featured ventilated disc brakes on all four wheels, offering ample stopping power. ABS (Anti-lock Braking System) and electronic stability control were standard features. The steering is a rack-and-pinion system with electric power assistance, providing precise and responsive steering feel. The suspension setup was generally softer than the AMG-tuned versions of the C-Class Coupe, prioritizing comfort over outright track performance.
Market Reception & Comparison
The C 300d 9G-TRONIC was generally well-received by automotive critics. It was praised for its refined engine, smooth transmission, and comfortable ride. Fuel economy was a significant selling point, with the C 300d offering competitive figures in its class. Compared to the C 300 gasoline variant, the C 300d was often seen as a more sensible choice for drivers who prioritize fuel efficiency and long-distance comfort. However, some critics noted that the diesel engine lacked the responsiveness and sound of its gasoline counterparts. Reliability reports have generally been positive, with the OM 654 engine proving to be a robust and durable unit.
Legacy
The C 300d 9G-TRONIC represents a significant step forward in diesel engine technology. The OM 654 engine has become a mainstay in the Mercedes-Benz lineup, known for its efficiency, refinement, and durability. On the used car market, the C 300d Coupe holds its value well, attracting buyers who appreciate its blend of luxury, performance, and fuel economy. With proper maintenance, the powertrain is expected to provide many years of reliable service, making it a compelling option for buyers seeking a premium coupe with a diesel engine.
