Hi Zacharias,

This is very simply a badging issue – Mercedes changed all its badging in 2015 and switched from ‘CDI BlueTec’, its old diesel nomenclature, to a straightforward ‘d’ postscript of the model name/number. AdBlue is an additive used in many diesels to reduce nitrous oxide emissions, so it is not uncommon in the industry and nor is the CLS the only car to use it. It is readily available to buy at filling stations and motor factors, as well as online.