New 1.6-litre engine for Citroen C5 07 April 2010 by Parkers French manufacturer updates 1.6-litre diesel for C5 range Fuel efficiency up by 6% with 56.5mpg fuel economy Free road tax and reduced BIK taxation rate Citroen has updated its 1.6-litre diesel engine on the C5 range. The new power plant is now leaner and greener. Available on all trim levels in both saloon and tourer, the 110bhp unit has improved fuel economy and better CO2 emissions. Fuel efficiency is up by 6% and the car averages 56.5mpg. Emissions have been slashed by 10g/km resulting in a total of 130g/km. The reduction is good news for company car drivers. Due to the 1-point reduction in BIK taxation rates, this variant of the C5 falls into the 18% bracket. A further bonus for new customers opting for the new 1.6-litre engine is that it qualifies for free road tax in the first year because it sits in VED band D.