Skip to content

FAQ AdBlue®

1. What is AdBlue®?

AdBlue® is an aqueous product comprised of 32.5% high purity urea* and of 67.5% deionised water, it respects the ISO22241 norm.

Urea is synthetically produced from ammonia and CO2 (carbon dioxide).

AdBlue® is used by vehicles equipped with the SCR technology (Selective Catalytic Reduction), such as heavy-duty trucks, buses, refuse collection vehicles, and, from September 2014, certain diesel passenger cars.

Biodegradable, soluble in water and colourless, AdBlue® cristallises at -11°C and decomposes into ammonia from 80°C (traces from 30°C).

AdBlue® is a registered trademark of the German Association of the Automobile Industry (VDA).

*What is urea?

Urea is a product from the agrochemical industry, mainly used for the production of fertilizers. It consists of ammonia (NH3) and carbon dioxide (CO2). Its chemical formula is CO (NH2)2. When heated, urea decomposes into gaseous ammonia. It is under this form that is transforms the nitrogen oxides (NOx) into nitrogen and into water (N2, H2O).


2. What is the use of AdBlue®?

Combined to the SCR technology, AdBlue® transforms 85% of NOx (nitrogen oxides resulting from the exhaust gases of your diesel vehicle) into harmless nitrogen and water steam. Therefore, NOx, which are a significant source of atmospheric pollution are considerably reduced.


3. Euro 5 and Euro 6 norms: why do I need AdBlue®?

To improve the air quality, the European Union regulates since 1990 the polluting emissions of exhaust gases with various European directives and regulations. Since then, several norms (Euro 1 to Euro 6) have been implemented in order to set lower and lower emissions limits. These anti-pollution European norms aim at reducing harmful emissions from exhaust gases, such as nitrogen oxides (NOx), hydrocarbons, carbon monoxide, and particulate matter. The SCR technology using AdBlue® is one of the systems chosen by car manufacturers to meet the EURO norms objectives and decrease polluting emissions.


4. What is the SCR technology?

SCR (Selective Catalytic Reduction) is the name of a post-combustion treatment technology for Diesel vehicles, converting nitrogen oxides (NOx) into water steam and nitrogen thanks to the use of AdBlue®. The air we breathe is composed of 80% nitrogen, which is totally harmless. With the heavy-duty vehicles emissions European Norms Euro 4 and Euro 5, almost all car manufacturers have decided to apply this technology to follow the new legislations on NOx emissions.  For passenger cars, SCR is only appearing in Europe from 2014 with the Euro 6 norm.

AdBlue® is injected into the exhaust pipe, located before the SCR catalyst and after the engine. When heated inside the exhaust pipe, AdBlue® decomposes into ammonia (NH3) and carbon dioxide (CO2). When the NOx react with the ammonia inside the catalyst, the harmful NOx molecules are transformed into harmless nitrogen (N2) and water (H2O).


5. Is my vehicle equipped with SCR technology?

To discover if your car is equipped with SCR technology, please check your vehicle’s owner manual or contact your dealership. If you notice an AdBlue® tank filler neck on your car, located next to the diesel tank filler neck, then your car is equipped with SCR.


6. Where is my AdBlue® tank filler neck?  

The location of the AdBlue® tank filler neck depends on the model of your vehicle. On some models, the AdBlue® tank filler neck is next to the Diesel filler neck. On others, the AdBlue® filler neck is inside the boot, and on other vehicles, it is under the bonnet. To get this information, you can ask your dealership, or see the owner manual of your vehicle. 


7. What is the capacity of the AdBlue® tank?

The capacity of the AdBlue® tank also depends on the model of your vehicle. In general, it varies between 8L and 25L. To get this information, you can ask your dealership, or see the owner manual of your vehicle.


8. What is the refill frequency of the AdBlue® tank?

As with fuel, several factors have an impact on consumption: the type of vehicle, the engine type, the vehicle load, the weather conditions (snow, wind, rain, etc.) and the driving style. In addition, the size of the AdBlue tank can vary considerably, so the refill frequency depends particularly on the vehicle.   

On heavy-duty trucks, a gauge indicates the level of AdBlue® left in the tank. On passenger cars, a warning light appears on the dashboard when 2400km of driving capacity remain (when this light appears it is time to refill).


9. Can I refill the AdBlue® tank myself?

Yes, this is possible. However, depending on the vehicle, the AdBlue® tank filler neck is more or less easy to access. Moreover, some vehicles need to have their dashboards reset to make the AdBlue® warning light disappear, which may require to go to the dealership.

Caution: If you see a service station selling AdBlue®, always ask if the pumps are designed to refill the tank of a passenger car. That is not always the case. It is likely that only heavy-duty trucks can refill at the pump. Indeed, heavy-duty trucks must often refill AdBlue®, sometimes weekly, so the station pumps are specially designed for their use (particularly the flow speed, adapted to the size of their tanks which is much bigger than that of passenger cars). 


10. What is the AdBlue® consumption compared to fuel consumption? Only for counsellors.  

As with the fuel consumption, the AdBlue® consumption differs, and depends on several factors: type of vehicle (camper, SUV, car, etc.), type of engine, driving conditions (mountain, with a trailer, caravan, etc.), driving style. For passenger cars sold between 2013 and 2016, the consumption of AdBlue® is around 1.5L every 100L of diesel.


11. Is AdBlue® sold at the service station compatible with my vehicle? 

The SCR technology is designed to work with a fluid meeting the ISO 22241 requirements. All AdBlue® labelled products respect this ISO norm, and ensure a proper functioning of the SCR, regardlees the brand of your car.

Car manufacturers only recommend AdBlue® labelled products, although other products may be used without risk for the SCR as long as they follow the ISO 22241 norm.  


12. If I refill AdBlue® myself, could I lose the manufacturer’s warranty?  

No, you are not taking any risk. However, be cautious: most car manufacturers will not accept the warranty claims if you use a product which does not comply with the ISO 22241 norm. The AdBlue® brand ensures that this norm is respected. The SCR systems are really sensitive to any chemical impurities in the urea solution. Using a qualitative product will help you avoid high repair costs or SCR replacement.  


13. What are the precautions of use of AdBlue®? 

AdBlue® is very easy to use and harmless. It is neither a fuel, nor a fuel additive, but a high quality urea solution that must remain in the dedicated tank on your vehicle. You refill the AdBlue® tank based on your needs. Caution: do not put AdBlue® into the diesel tank, or diesel into the AdBlue® tank, this would be very damaging for the engine and the catalyst.   


14. Is AdBlue® a dangerous product?

AdBlue® is non-flammable, non-explosive, and harmless for the environment. It is classified as a transportable liquid of minimum risk. If you spill AdBlue® on your hands or your clothes, simply rinse with water.


15. Does AdBlue® leave stains if I spill it? Only for counsellors.

AdBlue® can leave white stains and/or cause the floor to become slippery. If you spill AdBlue® on the floor, inside a vehicle, or on a painted surface, rinse with water. If you spill AdBlue® on your skin or on your clothes, you can remove it with water.


16. When does the « refill AdBlue® » warning light appear on the dashboard?  

This alert starts 2400km before you need to refill (this alert level is common to all vehicles and required by the norm). Your dashboard includes a warning light which will turn on when it is needed to refill your AdBlue® tank. But you don’t have to worry: you have a driving capacity of many hundreds or thousands kilometres remaining before having to refill AdBlue®. To turn this warning light off, you must refill the tank with at least 4L of AdBlue®.


17. Is there any other maintenance constraints? Only for counsellors.  

Your car SCR system is installed by the manufacturer, and works automatically. Therefore, you do not need to maintain, or change it. AdBlue® is automatically injected in the exhaust gases according to the engine speed of your vehicle. You can however confirm that your SCR system works properly by using only AdBlue® to preserve the efficiency of the SCR catalyst.  


18. Does AdBlue® have an impact on the engine performance? Only for counsellors.

AdBlue® has no direct effect on the performance of the engine. It helps reducing the polluting emissions to meet the standards of European norms. However, in case the AdBlue® tank is not refilled, the performance of the engine can be limited, or the vehicle stopped.


19. Does AdBlue® have an effect on my fuel consumption? Only for counsellors.

The use of SCR technology and AdBlue® enables the optimization of combustion, which can lead to a decrease of consumption for some vehicles. This reduction is already included into the figures claimed by car manufacturers.


20. What happens if I do not refill the AdBlue® tank? 

The first “refill AdBlue®” alert is turned on at 2400km remaining driving capacity. This timeframe is considered sufficient to allow the driver to refill AdBlue®.  

If you do not refill the tank, other alert levels will trigger depending on the distance travelled and the amount of engine restarts. First, these alerts will be visual and/or sound. Then, the engine performances will be limited by the vehicle. Last step is the impossibility to restart the car without refilling the AdBlue® tank.


21. What happens if I park my vehicle several days outside at a below -11°C temperature? Only for counselors.

Car manufacturers have normally taken this occasion into account and integrated an automatic warming system of AdBlue® in the tank, to allow the SCR catalyst to function properly within 20 minutes after engine start, according to the regulation.

If AdBlue® has crystallised in the tank, its performances are not weakened: the warming system will make it liquid again during the first 20 minutes to ensure that the SCR works properly.


22. What to do after an extended storage period? Only for counsellors. 

AdBlue® shelf life is superior to a year if it is stored at a temperature below 30°C. However, if the mileage driven by your vehicle is very low in view of the size of the tank, an AdBlue® change or renewal at the dealership should be considered. In that case, consult your owner manual, or contact your dealership.