Mercedes C-Class Cabriolet review
The refined Mercedes C-Class Cabriolet is one of our favourite four-seat luxury convertibles
When the Mercedes C-Class Cabriolet turned up for sale in dealers, it marked the first time that Mercedes had used the C-Class badge for its smallest four-seat convertible. Before its arrival in 2016, it was preceded by two generations of CLK Cabriolet, although both of these models were closely related to the respective C-Class models of the time.
The C-Class Cabriolet just about offers room for four - if you need a dedicated four-seat Mercedes convertible, there's always the slightly larger E-Class Cabriolet, or even the super-luxurious S-Class Cabriolet. As it stands, there's some crossover between the C-Class and E-Class convertibles in terms of rival manufacturers. The Audi A5 Cabriolet is between these two for size, as is the BMW 4 Series Convertible. There aren't many other rivals beyond these two, unless you count the quirky Range Rover Evoque Convertible, which carries a similarly premium price.
For the C-Class Cabriolet, those prices start from around £39,000, but that does mean only the most basic C 180 model avoids £450 road tax for the first five years you pay for it. The rest of the range comprises C 200, C 300, C 220d, C 300d, AMG C 43 and AMG C 63 variants, with decreasing economy and escalating performance on offer as you progress through the range.
Car group tests
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Used car tests
A major update in 2018 introduced new engines to the range, including Mercedes' latest 2.0-litre diesel, which is a lot more refined than the older 2.1-litre four cylinder. This engine powers both C-Class Cabrio diesels, including the C 300d. These models get Merc's 9G-Tronic auto as standard, while the C 200d has the option of 4MATIC four-wheel drive.
The petrol C 180 has a six-speed manual as standard and the 9G-Tronic as an option, and power comes from a 1.6-litre engine. The C 200 uses a smaller 1.5-litre petrol, but it adds Mercedes' EQ Boost hybrid assistance to boost performance and help with fuel economy. Like the C 300d, the petrol C 300 has a 2.0-litre turbo petrol engine. These cars also have a nine-speed auto, and the C 200 can be had with 4MATIC four-wheel drive.
Like the C-Class Coupe, the Cabriolet only comes in AMG Line trim. That means all cars are well equipped, with alloy wheels, all-round parking sensors, automatic parking, a reversing camera, LED headlights and DAB radio all included, as is Bluetooth connectivity and satellite navigation. Premium and Premium Plus packs add more kit in a better value package than speccing these options individually.
At the top of the range, the AMG models offer performance that makes the extra weight of the Cabriolet's chassis strengthening largely irrelevant. The C 43 has a 3.0-litre twin-turbo V6 with 390bhp and 4MATIC four-wheel drive, making it a fast and sure-footed family drop-top. There are two C 63 models, the 476bhp standard car and the 510bhp C 63 S, which manages 0-62mph in a faintly ridiculous 4.1 seconds, two tenths slower than the coupe.
The Mercedes C-Class Cabriolet is a superbly refined and beautifully finished convertible. When cruising four-up with the top down, the C-Class excels. It’s not as sharp to drive as an Audi A5 Cabriolet, but it’s a better convertible and packed with handy features to make life more comfortable.
Performance from the diesel engine isn't electrifying and the car can be a little noisy, but take it easy and the Mercedes shines. It feels like a miniature version of the flagship S-Class Cabriolet, but at half the price. That's one reason why it was the best convertible in the 2017 Auto Express New Car Awards.
Engines, performance and drive
Roof-down cruising in the C-Class Cabriolet is enjoyable at any speed, courtesy of the Aircap system. While the raised windscreen header rail looks a bit unsightly when it’s up, and does generate some wind noise at high speeds, it deflects airflow over the cabin so effectively that you can cruise at motorway speeds and remain untroubled by buffeting.
Combine Aircap with the deflector behind the back seats when you have all the windows raised, and the C-Class is remarkably refined when driving with the top down. It’s the same story with the roof up, as the multi-layered hood is quiet even at motorway speeds.
In corners it’s immediately clear the heavy Mercedes isn’t as agile as the Audi A5 Cabriolet. The steering is direct and well weighted and there’s plenty of grip, but body movements aren’t as well controlled and it responds to direction changes more lazily.
However, Mercedes has done a good job in strengthening the car’s bodyshell during its transition from coupe to convertible. Severe bumps result in some flex, but the movement is small and doesn’t upset the car’s composure.
This chassis stiffness has further benefits for the ride, which is reasonably smooth at low speed and supple on the motorway. It’s not perfect, though, with sharp ridges sending a sickening crash through the structure.
In other respects, refinement is good. As with the Audi, there’s more wind and noise with the roof up than in the coupe, but it’s far from intrusive.
There is a range of engines available in the drop-top Mercedes C-Class but the most popular will be the C 220d, which has replaced its noisy 2.1-litre diesel with a smoother 2.0-litre unit from the E-Class. It has also been given a power boost, up to 194bhp from the old car's 168bhp output, so the C-Class now has the firepower to outgun the Audi A5 Cabriolet with the 2.0 TDI 190 diesel. There's 400Nm of torque like before, which is a match for the A5’s. In combination with the closely stacked ratios of its nine-speed gearbox, the C 220 d can sprint from 0-60mph in 7.5 seconds, which is faster than the Audi.
In the real world there’s little to separate the C 220 d with the A5 2.0 TDI. The C-Class’s 2.0-litre diesel matches the A5’s 2.0 for smoothness and refinement, the responsive nine-speed auto keeps the engine in the muscular mid-range, so you can make brisk progress without having to extend it.
Above the entry-level C 220d diesel sits the C 300d, which uses the same engine boosted to 245bhp. On the petrol side, there’s the C 180 with a 156bhp 1.6, the C 200 with a 184bhp 1.5-litre petrol engine combined with the 14bhp EQ Boost hybrid tech, and the C 300 which uses a 2.0-litre turbocharged engine to make 258bhp.
If you feel you need even more performance, Mercedes-AMG can help. The line-up opens with the C 43 4MATIC with its 362bhp V6 unit and then you can step up to the full-fat C 63 with its 4.0-litre V8 with 476bhp or 510bhp in S guise.
MPG, CO2 and Running Costs
Prices for the C-Class Cabriolet start from just under £40,000, so the only version that costs £140 a year in road tax from new is the entry-level C 180 petrol with the manual gearbox. All other cars will cost £450 a year in road tax for the first five years that you pay it.
As with the hard-top cars in the Mercedes C-Class range, if you want rock bottom running costs, your best bet is the range of diesel models. The entry level C 220d diesel returns up to 49.8mpg on the WLTP test cycle, while emissions are 126g/km on 18-inch wheels and 136g/km if you go up an inch in size. Despite the C 300d being more powerful it returns up to 47.1mpg and emits 138g/km of CO2 (151g/km on 19-inch wheels) but it is more expensive to buy.
The petrol engines are, of course, smoother - but they do cost more to run day-to-day. The most efficient is the C 180, capable of 41.5mpg and CO2 emissions of 149g/km. Above that sits the more powerful C200, but economy drops to 40.4mpg, but emissions stay the same. The C 300 weighs in with 37.7mpg economy, whle the C 43, and C 63 cars have economy ranging from 28.5mpg at best to a low score of 24.4mpg for the most powerful S model.
Insurance groups start at 31 for the C 220d AMG Line and rise to 48 for range-topping the Mercedes-AMG C63 S
Residual values of 45% for the C 220d are nothing to write home about, and pretty much average for the class.
Interior, design and technology
The Mercedes C-Class Cabriolet is a wholly conventional-looking four-seater drop-top. However, that doesn’t mean it blends into the background, because Mercedes has found its design mojo. This car stands out with its combination of swooping lines and neat detailing. It largely shares the C-Class Coupe’s elegant lines, albeit with a fabric roof in place of that car’s tin-top.
Up front, the grille is adorned with a large three-pointed star (which houses some of the sensors for the electronic driving aids), and there's a pair of LED headlamp clusters with distinctive daytime running lights. Curves arch back from the nose, along the car’s flanks to the tail, where the rounded rear and slender lamps complete the look.
Overall, the C-Class Cabriolet resembles a shrunken version of the S-Class Cabriolet, while AMG Line models add a sharp bodykit, 18-inch five-spoke alloy wheels and a diamond-finish grille. The soft-top can be ordered in a variety of contrasting colours for no extra cost. The roof is a little slower to operate than rivals’, taking 18.3 seconds, but you can do this at speeds of up to 37mph.
Sat-nav, stereo and infotainment
Inside, the car has the same upmarket feel as the C-Class saloon, with plenty of metal switches and high-grade plastics throughout. You get Mercedes’ familiar tablet-style infotainment screen on top of the dash, controlled via the COMAND wheel ahead of the central armrest, and the Cabriolet adds a bank of three switches behind that for the roof, Aircap and four-window opening controls.
Aircap is the manufacturer’s name for the wind deflectors on top of the windscreen header rail and behind the back seats, and it’s fitted as standard on the Cabriolet. The Airscarf neck heater is also included, as are heated seats, sat-nav, those LED headlights and Artico synthetic leather. If you want more luxury, Mercedes offers Premium and Premium Plus packages that add goodies such as LED ambient lighting, a high-end Burmester stereo and memory seats.
Practicality, comfort and boot space
If you’re going for a convertible, some sacrifices are always going to have to be made. Firstly, the Mercedes C-Class drop-top only seats four people rather than five, but at least you can get two adults in the back. The front seat can be electronically slid forward to make access easier. Up front, the convertible is identical to the coupe, so you get the same amount of storage areas and cubbies.
Leg room, head room and passenger space
Space up front is identical to the coupe, but those in the back will be a little more cramped. Knee room is decent, though, and on par with the BMW 4 Series.
There’s just about enough space for adults in the rear but getting in and out can be a little tricky. However, its made infinitely easier if the roof has been stowed away.
The biggest issue with the C-Class Cabriolet is the size of the boot. To allow the folding fabric roof to be stowed away, Mercedes has had to reduce the size of the luggage space quite dramatically. When the roof is down, space is reduced to just 260 litres – a huge drop form the 480 litres you can get in the saloon.
Reliability and Safety
The Mercedes C-Class Cabriolet uses the same platform as the C-Class saloon, so that car’s five-star Euro NCAP rating (earned in 2014) applies here. You still get seven airbags, while park assist, tiredness recognition and city braking are all included. Rollover protection is also deployed if the worst should happen.
If you specify the Driving Assistance Package (around £1,700), blind-spot assist, lane keeping and adaptive cruise control are added to the kit list. Mercedes’ dealers were rated more highly than Land Rover’s in our Driver Power 2016 satisfaction survey, but a 20th-place finish isn’t great. Still, the network ranked ahead of those of BMW and Audi.
Like all Mercedes, the C-Class Cabriolet comes with a three-year, unlimited-mileage warranty.
Mercedes offers a service plan on the Cabriolet for around £35 per month, but this works out at £1,260 over three years.