What Is AdBlue And How Does It Work

Many new diesel cars use a fluid called AdBlue. If your car uses AdBlue, you’ll probably need to top it up at least once between services.Find out what it does, how it works and why it’s important to keep an eye on dashboard warnings – particularly if you’re a high-mileage motorist.AdBlue is an exhaust fluid, not a fuel additive. It’s stored in a separate adblue Audi reservoir and is topped up via a (usually) blue filler cap located either next to your fuel filler, in the boot or under the bonnet. It’s a trade name registered by the German car manufacturers association, but is the most recognised form of Diesel Exhaust Fluid (DEF).

Lots of people think AdBlue is made of pig urine – it’s not. The urea used in AdBlue is a high-purity man-made solution – pig urine wouldn’t be pure or sterile enough for a commercial product.Tiny amounts of AdBlue are injected into the flow of exhaust gases. At high temperatures AdBlue turns to ammonia and carbon dioxide. If you run out of AdBlue while you’re driving, then the engine’s power and performance will be reduced to limit its emissions. Once you’ve stopped, you won’t be able to restart the engine if the AdBlue tank’s empty.

The car will give you plenty of warning that the AdBlue tank is running low. You’ll usually see a text warning on the dashboard when there’s around 1500 miles’ worth of AdBlue left. Inside the SCR (Selective Catalytic Reduction) catalyst, harmful nitrogen oxide in the exhaust reacts with the ammonia and is transformed in\to harmless nitrogen and water.