Diesel exhaust fluid (DEF; also known as AUS 32 and sometimes marketed as AdBlue[3]) is a liquid used to reduce the amount of air pollution created by a diesel engine.

AdBlue is a liquid that’s added to diesel vehicles exhaust to help reduce harmful exhaust emissions (NOx). It turns harmful pollutants into harmless gases that do less damage to the …

Nov 26, 2025 · AdBlue is a diesel exhaust fluid (DEF) that helps reduce a diesel vehicle’s NOx exhaust emissions. It’s stored in a tank with a blue filler cap, which is separate from the fuel tank.

Nov 7, 2025 · AdBlue is the brand name of a diesel exhaust fluid that’s owned by the German Association of Automotive Industry. It’s not a fuel additive but is meant to be used with newer …

AdBlue® is an aqueous solution designed exclusively for diesel vehicles fitted with a selective catalytic reduction (SCR) system. This technology has enabled diesel vehicle manufacturers to …

Jul 6, 2025 · You've surely heard of brake fluid, fuel, and lots of other liquids needed to run a diesel vehicle. But what's AdBlue fluid? And do all diesel vehicles need it?

If you've seen bottles of AdBlue at filling stations and wonder what it's for and whether your car needs it, our guide will tell you everything you need to know.