Although diesel has yet to take a real foothold in the North American passenger car market, it’s spread through Europe like a medieval plague. In certain markets, diesel models account for 70% of BMW’s sales, which is why the German manufacturer has put so much effort into producing probably the best diesel engines in the world.

Star of the show is the twin-turbo 3.0 turbo-diesel motor found in almost every BMW model line-up. In fact, a version slightly modified to meet emissions regulations is available in the US in the 335d and and X5 xDrive35d.
This engine has also found its way under the hood of the 6-Series, in the form of the 635d, and during a recent trip to England we had the opportunity to drive a Convertible with the Sport package.
To our way of thinking, a diesel convertible in Britain is anathema. With the unpredictable weather, why would you put the hood down and risk being caught in the rain, only to be choked by diesel fumes when you do?
However, BMW claims this is the world’s only luxury 2+2 grand touring diesel convertible. So the car actually makes good sense in Britain, where taxes on large engines make diesels a popular option. And the fast-operating soft-top means you can avoid the worst of a sudden downpour.
The 635d joins a model line-up that includes a 630i, 650i and M6, offering Europeans plenty of choice and a wide price range for their motoring enjoyment.
With 286hp and a monstrous 430 lb-ft of torque available from just 1750rpm, the 635d is no regular diesel. It accelerates to 62mph in 6.6sec (6.3 for the Coupe) and is limited to 155mph. Yet it whisks you along while sipping 29mpg on the urban cycle, 49mpg on the extra-urban cycle and 39mpg combined.
To be honest, we didn’t see the higher numbers. Maintaining about 32mpg on combined driving was about the best we could do, but we must confess we weren’t hanging around. The intoxicating flow of torque tempted us to keep pushing the paddles on the steering wheel to select a different gear and enjoy the rush all over again.
Being a Sport model, our 635d had 19” wheels, sports seats, an M steering wheel and sport auto transmission among its huge list of options. One of the cleverer additions was a lane departure warning that would vibrate the steering wheel if you crossed a lane marker without indicating – this proved useful when trying to select music or nav options from the new, improved and surprisingly logical iDrive system.
It’s hard to believe we’re attributing such qualities to the iDrive, but BMW has finally added enough buttons and altered its interface sufficiently to finally produce the helpful tool they always promised. Inputting an address or finding a fuel station was now relatively simple. And choosing your source of music or connecting a Bluetooth phone was a breeze. Hallelujah. BMW finally solved our biggest irritation and has produced a viable infotainment system.
The combination of a torquey yet frugal engine in a Convertible with the appeal of the 6-Series makes the 635d one of the more sensible options on the road today, particularly if you’re looking for something with style. And not being penalized at the gas pump was a real bonus. This car definitely offers the best of both worlds.