Hi Ossie,

BlueTec is Mercedes’ brand name for its system of selective catalytic reduction (SCR) or, in English, treating the exhaust gas of a diesel engine to reduce its emissions. BlueTec basically squirts a spray of AdBlue solution into the exhaust, which dramatically reduces the emissions of nitrogen oxide or NOx, the nasty lung-disease-causing gas that’s been at the heart of the recent debate over diesel air quality. So, a BlueTec car has the spray system, and a non-BlueTec car does’t. The good news is that a BlueTec car is therefore cleaner and better for both the environment and public health, but it does mean keeping the AdBlue tank topped up.