BMW 6-Series Convertible (2011-2018) running costs and reliability

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Running costs rating: 3.5 out of 53.5

Written by Tim Bowdler Published: 6 June 2019

Miles per pound (mpp)

Reliable fuel consumption data for comparison purposes is not available for this model.

What is miles per pound?

Fuel economy

A more stringent standard for fuel economy (WLTP) was introduced from September 2017, and this model was not required to undergo that test. Its fuel economy measured under the previous test system was 26 - 50 mpg. However these figures are less likely to be achievable in real world driving and so should never be compared to another car's mpg which was measured under the newer, more realistic WLTP system.

View mpg & specs for any version

Achieving an average of 35.8mpg is very impressive. You’ll need to keep the car in comfort or normal mode to achieve the optimum fuel return but flick the lever into Sport+ and you’ll soon be back at a filling station. BMW dealers can be expensive but service is usually first class.

CO2 emissions are 185g/km for the 640i – that’s road tax band I. However, buy the 650i and it emits a whopping 249g/km of CO2 – this places it in band L. To see the cost of annual tax as well as first-year showroom tax, visit the Parkers road tax calculator. The car features the Efficient Dynamics programme. These include Brake Energy Regeneration, lightweight engineering and Electric Power Steering.

On the 640i derivative things are taken a stage further with the implementation of start/stop and active aerodynamics behind the car’s kidney grille – the former being a technology that is unique in its segment.

Few problems have been reported with the previous generation. Expect issues to be few and far between.