Getting to know AdBlue®

This week in our “Getting to Know” series, we take a look at AdBlue® for diesel cars which some consumers have contacted The Motor Ombudsman’s Customer Service Advisors about.



What is AdBlue?  


AdBlue®, a registered trademark owned by the German Association of the Automobile Industry (VDA), is a non-toxic, non-flammable biodegradable urea and water-based liquid additive. It’s not a fuel. The fluid is stored in a tank within the vehicle, but is not injected into the engine. It is instead fed into part of the vehicle’s exhaust.


How does AdBlue® work?  


AdBlue® converts harmful nitrogen oxides (NOx) in the exhaust of a diesel car into harmless nitrogen and steam, therefore considerably reducing the level of (NOx) that is emitted into the atmosphere and the surrounding environment.


How do I know if my car uses AdBlue®?  


In most diesel-powered vehicles, there will be a light blue filler cap next to the black diesel fuel filler cap. However, it can also be found in the boot or engine compartment of some cars. The vehicle handbook will let you know where it is.


How much AdBlue® does a car use and how often does it need to be topped up?  


A car consumes around one to one and half litres of AdBlue® approximately every 600 miles dependent on the model of the vehicle and the driving style of the owner. The car’s dashboard or driver information system will provide a notification if it needs to be topped up, but garages should refill AdBlue® as part of a diesel-powered vehicle’s routine servicing schedule. It is possible to refill a tank of AdBlue yourself by using a portable container which can be purchased at selected retailers or a petrol station.


Does the type of AdBlue® affect my warranty?


If the vehicle is under warranty, it is important to use a branded AdBlue® solution. For any solution to use the registered trademark, it must comply with certain standards that vehicle manufacturers’ SCR systems rely on. Failing to do so could invalidate the warranty.


Look for the ISO 22241 number on the packaging. This may also appear as ISO-22241-1, ISO-22241-2 or ISO-22241-3.


Where can I find a garage to get the AdBlue® topped up?


To find your local Motor Ombudsman-accredited dealer or independent garage, visit


Image courtesy of Volkswagen UK