The Mercedes-Benz C-Class Cabriolet (A205), particularly the C 300d variant with the 9G-TRONIC automatic transmission, represents a compelling blend of luxury, performance, and efficiency within the premium mid-size convertible segment. Introduced with the A205 facelift in 2018 and continuing through 2023, this model aimed to deliver a sophisticated open-air driving experience while leveraging advancements in diesel technology. Positioned as a mid-to-upper trim level within the C-Class Cabriolet range, the C 300d offered a step up in performance and refinement compared to the base C 200d models, while remaining more accessible than the higher-performance AMG variants.
Technical Specifications
| Brand | Mercedes-Benz |
| Model | C-class |
| Generation | C-class Cabriolet (A205, facelift 2018) |
| Type (Engine) | C 300d (245 Hp) 9G-TRONIC |
| Start of production | 2018 |
| End of production | 2023 |
| Powertrain Architecture | Internal Combustion engine |
| Body type | Cabriolet |
| Seats | 4 |
| Doors | 2 |
| Fuel consumption at Low speed (WLTP) | 5.7 l/100 km (41.3 US mpg, 49.6 UK mpg, 17.5 km/l) |
| Fuel consumption at very high speed (WLTP) | 6.6 l/100 km (35.6 US mpg, 42.8 UK mpg, 15.2 km/l) |
| CO2 emissions (WLTP) | 149-172 g/km |
| Fuel consumption (economy) – urban | 6.1-6.7 l/100 km (38.6 – 35.1 US mpg, 46.3 – 42.2 UK mpg, 16.4 – 14.9 km/l) |
| Fuel consumption (economy) – extra urban | 4.7-5.2 l/100 km (50 – 45.2 US mpg, 60.1 – 54.3 UK mpg, 21.3 – 19.2 km/l) |
| Fuel consumption (economy) – combined | 5.2-5.7 l/100 km (45.2 – 41.3 US mpg, 54.3 – 49.6 UK mpg, 19.2 – 17.5 km/l) |
| CO2 emissions | 138 – 151 g/km |
| Fuel Type | Diesel |
| Acceleration 0 – 100 km/h | 6.3 sec |
| Acceleration 0 – 62 mph | 6.3 sec |
| Acceleration 0 – 60 mph | 6 sec (Calculated) |
| Maximum speed | 250 km/h (155.34 mph) |
| Emission standard | Euro 6 |
| Weight-to-power ratio | 7.1 kg/Hp, 140.4 Hp/tonne |
| Weight-to-torque ratio | 3.5 kg/Nm, 286.5 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 | 1745 kg (3847.07 lbs.) |
| Max. weight | 2285 kg (5037.56 lbs.) |
| Max load | 540 kg (1190.5 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 | 1409 mm (55.47 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 | 12.6° |
| Drivetrain Architecture | Rear wheel drive |
| 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 |
INTRODUCTION
The A205 C-Class Cabriolet, launched in 2016 and receiving a significant facelift in 2018, brought open-top motoring back to the C-Class lineup after a long hiatus. The C 300d 9G-TRONIC, introduced with the facelift, combined a potent four-cylinder diesel engine with a sophisticated nine-speed automatic transmission. This combination aimed to provide a balance of performance, fuel efficiency, and comfort, appealing to buyers seeking a refined and capable convertible. Built on the Mercedes-Benz MRA (Modular Rear-wheel Architecture) platform, the A205 shared its underpinnings with the C-Class sedan and coupe, ensuring a high level of structural rigidity and driving dynamics.
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 key component of Mercedes-Benz’s modular engine family, known for its advanced technology and efficiency. It features a high-pressure common rail direct injection system, delivering fuel at up to 2,700 bar for optimized combustion. The engine also incorporates a variable geometry turbocharger (VGT) and intercooler to enhance power and torque across a broad rev range. The 9G-TRONIC automatic transmission, a nine-speed unit, is designed to maximize fuel efficiency and provide smooth, seamless gear changes. It features a wide gear ratio spread, allowing the engine to operate in its optimal efficiency zone more frequently. The transmission also includes a torque converter lockup clutch to minimize energy loss.
Driving Characteristics
The C 300d 9G-TRONIC delivers a surprisingly brisk driving experience for a diesel-powered convertible. The 500 Nm (368 lb-ft) of torque, available from 1600-2400 rpm, provides strong acceleration in everyday driving situations. The 0-60 mph sprint takes approximately 6 seconds, and the car feels responsive and capable on the open road. The 9G-TRONIC transmission contributes to a relaxed cruising experience, with well-spaced gear ratios and smooth shifts. Compared to the C 200d, the C 300d offers a noticeable performance advantage, while remaining more fuel-efficient than the gasoline-powered C 300. The automatic transmission, while convenient, doesn’t offer the same level of driver engagement as a manual gearbox, but its efficiency and smoothness are well-suited to the C-Class Cabriolet’s grand touring character.
Equipment & Trim Levels
The C 300d Cabriolet typically came well-equipped as standard, including features such as leather upholstery, automatic climate control, a high-resolution infotainment system with navigation, and a suite of driver-assistance systems like collision prevention assist and attention assist. Optional extras included features like the AIRSCARF system (which directs warm air onto the occupants’ necks), premium sound systems from Burmester, and advanced driver-assistance packages with features like adaptive cruise control and lane keeping assist. Interior trim options ranged from aluminum to wood finishes, allowing buyers to personalize the cabin to their preferences.
Chassis & Braking
The A205 C-Class Cabriolet benefits from a robust chassis designed to minimize scuttle shake – a common issue in convertibles. The suspension system consists of independent multi-link suspension at all four corners, providing a comfortable ride and good handling characteristics. The C 300d typically featured slightly stiffer springs and dampers compared to the base models to cope with the increased power and torque. Braking duties are handled by ventilated disc brakes on all four wheels, providing ample stopping power. ABS (Anti-lock Braking System) and electronic stability control are standard features, enhancing safety and control.
Market Reception & Comparison
The C 300d Cabriolet was generally well-received by automotive critics, who praised its refined driving experience, comfortable interior, and fuel efficiency. The diesel engine was noted for its quiet operation and strong performance. Compared to its rivals, such as the Audi A5 Cabriolet and BMW 2 Series Convertible, the C 300d offered a compelling combination of luxury, performance, and technology. Fuel economy was a strong point, with the C 300d achieving real-world figures in line with the official WLTP ratings. Reliability has been generally good, although some owners have reported minor issues with the infotainment system.
Legacy
The Mercedes-Benz C 300d Cabriolet (A205) represents a significant step forward in diesel-powered convertible technology. The OM 654 engine is known for its durability and efficiency, and the 9G-TRONIC transmission provides a smooth and refined driving experience. On the used car market, these models hold their value well, particularly those with low mileage and a full service history. The C 300d remains a desirable option for buyers seeking a luxurious and capable open-top car that offers a good balance of performance, fuel economy, and comfort.
