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16/07/2019 News

The ultimate guide to Adblue




If you own a diesel, chances are you need to use AdBlue® – a diesel exhaust fluid (DEF) used in millions of cars, light commercial vehicles, HGVs, buses and coaches across the world. But what is it, what does it do, how does it work and how do you best use it to ensure your car performs efficiently and safely? Read on to learn more and have all your AdBlue® questions explained.​


What is AdBlue?

AdBlue® is a diesel exhaust fluid (DEF) mixture used in all heavy-duty diesel engines produced after January 1st, 2010 and most passenger diesel engines made after September 2015 – primarily Euro 6-compliant models. AdBlue® is not a fuel additive as it’s added to the exhaust gas after combustion has taken place.

AdBlue® reduces Nitrogen Oxide (NOx) emissions. Nitrogen oxide is a harmful gas that can damage the respiratory system, reducing lung function, increasing allergen exposure and the risk of respiratory illnesses. Its presence promotes the formation of fine particulate pollution and ground ozone – harmful to both health and vegetation.

It’s for these reasons that governments set limits on vehicular NOx emissions. This improves air quality and reduces the danger of diesel pollution-related illness and death.

The term AdBlue® is a worldwide trademark of the German Association of the Automotive Industry (VDA) relating to DEF produced in accordance with the ISO 22241 specifications.


What is AdBlue made of?

AdBlue® is a colourless mixture of high-purity urea (32.5%) and deionised water (67.5%), as set out in the ISO 22242 standard.


What does AdBlue® do? How does it work? ​

AdBlue® engines use selective catalytic reduction (SCR) technology to reduce nitrogen oxide (NOx) exhaust emissions. They can usually be identified by the use of ‘SCR’ or ‘Blue’ in the vehicle’s model name.

As AdBlue® enters the SCR catalytic converter it is sprayed into the exhaust gas via a dosing control system. Here, the ammonia within the urea reacts with NOx in the exhaust to form harmless nitrogen (N2) and water vapour (H2O), while reducing total fuel consumption by 2-6%.


Is all AdBlue® the same?

While there are different names for AdBlue®, such as Bluedef, BlueTec and so forth, all mixes should contain the same solution of 32.5% urea and 67.5% de-ionised water. The German Association of the Automotive Industry’s AdBlue® marque can be confidently relied upon to meet these requirements, while others may not.

You should not use water instead of AdBlue®. The VDA notes that vehicles should not use urea solutions not denoted by the ‘AdBlue’ trademark. While inexpensive, these can be dangerous, damage the engine, affect steering and harm the SCR catalytic converter, so it’s always best to stick with legitimate, branded AdBlue®.

Does my car need AdBlue®?

If your car is a diesel, there is a high chance it will require AdBlue®. If you’re unsure, consult your vehicle’s handbook, or search for the filler cap located next to the fuel filler, under the bonnet or in the boot of the vehicle.

How long does AdBlue® last and how much AdBlue® should I use?

The rate at which your AdBlue® depletes is around 1 litre for every 350 to 600 miles. The exact rate depends on engine size, driving style and the size of the tank, which varies in size between 5 and 20 litres. For more information, consult your vehicle’s handbook or a qualified mechanic.

Driving without AdBlue® – can you do it?

It’s impossible to drive without AdBlue® – your engine will not start, and you’ll see a notification noting ‘AdBlue® is empty’. A notification will also appear when your AdBlue® tank is running low.

Most diesel vehicles require an AdBlue® top-up every 3,000-4,000 miles, depending on the engine. Check your vehicle manual for a figure specific to your make and model.

How much does AdBlue® reduce emissions?

AdBlue® is generally considered to reduce NOx emissions by over 90%, making it a crucial tool for improving air quality and combatting environmental issues.

Which cars use AdBlue®?

If your diesel vehicle was registered after September 2015, it likely uses AdBlue®. Often, the model name will feature the words ‘SCR’ or ‘Blue’, and if the vehicle is produced by a European manufacturer, the use of AdBlue® technology is more likely.

What is the freezing point of AdBlue®?

AdBlue® can freeze at temperatures below -11°C, however it will usually thaw due to the heat of the engine in cold winter conditions, without any change in concentration or effectiveness.

If driving in exceptionally cold conditions, it can be a good idea to keep a bottle of liquid AdBlue® in your vehicle to top up the tank in case of freezing – automatic warming systems can take up to 20 minutes to thaw frozen AdBlue® tanks.

Is AdBlue® corrosive, toxic or dangerous?

AdBlue® DEF is water soluble, biodegradable and non-hazardous, however you should rinse thoroughly in case of contact, avoid AdBlue® vapours, and clean surfaces that come into contact, as it is slightly corrosive to certain materials.

Total's AdBlue® products 

Total offer AdBlue® in bulk, barrel and small commercial vehicle packs, and offer all the benefits of fully compliant AdBlue® to drivers and fleet operators.

As well as reducing NOx without harming engines, Total AdBlue® also features Total Diaxol, an additive within the solution that cleans SCR systems, improving their cold and stop-start performance. Reducing clogging in exhaust, Diaxol has been shown to remove the risk of clogging for up to 50,000km and reduce maintenance costs.

Learn more about how Total AdBlue® and Diaxol can improve your fleet emissions and lower maintenance costs today.