All you need to know about AdBlue®

March 17, 2023
Engine AdditivesContact

AdBlue® is an exhaust fluid, not a fuel additive and must only be added to the AdBlue® tank which is located next to the diesel filler cap. The tank usually has a blue filler cap.

It is usually recognised as Diesel Exhaust Fluid (DEF) AdBlue® is the registered brand name.

What is AdBlue® made of?

It is a colourless non toxic liquid mixture of urea and deionised water, The urea is a man made chemical. AdBlue® has a shelf life of 12 months before crystallisation can start to take place. The date of manufacture is stamped on the container.

Tiny amounts of AdBlue® are injected into the flow of exhaust gases and due to the high temperature of the exhaust gases the AdBlue® turns into ammonia and carbon dioxide which inside the catalyst reacts with the harmful nitrous oxide in the exhaust  and transforms this into harmless nitrogen and water.

Which cars can use AdBlue®?

Diesel vehicles produced after September 2015 with an Euro 5 or Euro 6 engines.

You can check in your vehicle manufacturers handbook. This applies to both passenger cars and commercial vehicles.

How much AdBlue® does a car use?

The AdBlue® is normally monitored by the vehicle and will advise when the tank is getting low to enable you to top up well in advance. Passenger cars tanks vary, between 10-20litres. Commercial vehicles can be between 20 – 50 litres. Typically a passenger car will use 1 litre every 600 miles.

AdBlue® can normally be purchased in 5,10,20 litre containers, usually sold with a funnel/spout to allow easy pouring into the tank.

What happens if warning lights come on?

A warning light will come on giving you plenty of time to refill the tank. The distance to empty will count down each time you use the vehicle.Normally the countdown starts at approx. 1500 mile to go.

If the AdBlue® runs out while you are driving the engines power and performance will be reduced to limit its emissions. Often referred to as going into limp mode. Once you have stopped you wont be able to start the vehicle until replenishing the AdBlue® tank. Once the tank has been topped up then the warning light will go out.

What happens if I put AdBlue® in the diesel tank?

Putting AdBlue® directly into the diesel tank could cause expensive damage to your fuel tank, pump and injection system. If you start the engine its likely to be an expensive bill. You will need to get your diesel tank drained and the contents disposed of safely, before refilling it.