• myAutomate

What is AdBlue?

Ever wondered what all those plastics bottles piled up at the petrol station are? Or perhaps you’ve purchased a newer diesel vehicle recently and noticed a blue filler cap next to the diesel cap.

AdBlue’s introduction largely coincided with the more stringent emissions targets that vehicle manufacturers were required to meet. Without AdBlue, it would be significantly harder to lower the emissions of diesel-fuelled vehicles.

The introduction of the latest Euro 6 standards, applied to new models from September 2014 and all-new diesel cars from September 2015, demanded a 67% drop in Nitrogen Oxides (NOx) in the exhaust emissions of diesel cars.

NOx gases cause respiratory problems and contribute to the formation of particulate matter, smog, acid rain and ground-level ozone.

What is AdBlue and what does it do?

Stored in a separate tank on a diesel vehicle, AdBlue is the trade name registered by the German car manufacturers association. It is the most recognised form of Diesel Exhaust Fluid (DEF).

When the car’s engine is running, tiny amounts of AdBlue are injected into the car’s exhaust, breaking down harmful nitrogen oxide emissions into harmless nitrogen and water vapour.

What is AdBlue made of?

AdBlue is a colourless liquid solution composed of 32.5% urea and 67.5% high-quality de-mineralised (de-ionised) water. Urea is produced naturally by mammals, but it was also one of the first natural fluids to be recreated in a laboratory. The urea used in AdBlue is a highly pure laboratory-produced solution.

The other part of AdBlue is the de-ionised water, made by removing mineral ions such as iron, chloride and sodium.

Which cars need AdBlue?

The majority of diesel cars registered after September 2015 use AdBlue to reduce their emissions. In general, if your vehicle is Euro 6 compliant, it is likely to use AdBlue.

Manufacturers such as Audi, BMW, Jaguar Land Rover, Mercedes-Benz and Peugeot use AdBlue technology.

Cars such as the Audi A4 have a 12 litre AdBlue tank, which should last for over 6,000 miles in normal driving conditions.

What happens if you run out of AdBlue?

If you run out of AdBlue, the performance of the engine deteriorates, and once you stop driving, you won’t be able to restart the engine. Your car will give you plenty of warning that the AdBlue tank is running low, typically around 1200 miles.

In the years immediately after the introduction of AdBlue, there was a glut of AdBlue related breakdowns. In the 12 months to June 2018, the AA reported seeing 23,000 AdBlue associated breakdowns. This number started to decline in 2019, coinciding with a decrease in the sales of diesel cars. The AA praised fleet managers for educating drivers around the use of AdBlue but said people must continue to take note of AdBlue levels in their diesel vehicles.