AdBlue: Facts, myths, and usage

More and more trucks are requiring AdBlue to run. This infers an extra cost, which can be hard to calculate. But what is AdBlue, how does it reduce greenhouse gas emissions, and what happens if you fail to use it?

A highly purified diesel exhaust fluid (DEF), AdBlue is a non-toxic, non-flammable, odourless solution containing 32.5% high purity water and 67.5% deionised water. Here are the answers to most questions transport operators have about its usage:

Why is AdBlue needed?

The transport industry is the biggest contributor to greenhouse gas emissions; diesel vehicles and equipment account for almost half of all nitrogen oxides (NOx). Vehicle manufacturers face pressure to minimise the substantial harmful emissions released by diesel exhausts.

How does AdBlue fluid work?

Polluting chemicals and compounds, including NOx and nitrogen dioxide, are produced when diesel engines burn fuel. These elements build up in the air, producing smog and acid rain. AdBlue works through a process called selective catalytic reduction (SCR). Before any emissions are released, the solution is added into a diesel exhaust as a fine spray, at a proportion roughly equal to 5% of the diesel fuel. This releases ammonia, which is a catalyst for a chemical reaction that converts dangerous chemicals into nitrogen, water vapour, and a minimal amount of CO₂*, none of which harm our lungs.

What happens if I run out of AdBlue/don’t use AdBlue?

When your SCR-equipped truck’s AdBlue levels run low, a warning alert will appear on the dashboard. If it runs out completely, the truck will lose power. Engine performance will be returned when the AdBlue tank is replenished. Running out of AdBlue will not damage an engine.

How long does AdBlue last and how do I store it?

Storing AdBlue is straightforward, although it must be kept at 11 to 30°C to maximise its 12-month expectancy.

Is AdBlue hazardous?

AdBlue is not a hazardous substance and has no known negative effects or critical hazards. Urea is a raw material that occurs naturally in our digestive system. However, you should never inhale or ingest AdBlue. It is corrosive, and can dissolve materials not listed as AdBlue proof in ISO 22241, which could cause malfunctions in your SCR catalyst. You may want to wear gloves when dispensing AdBlue to keep your hands clean. While AdBlue can easily be washed off with water, it may stain clothing.

What do I do if I spill AdBlue fluid?

AdBlue isn’t hazardous to the environment, so you can dilute a small spill with water and simply mop it up. For a large spill, make sure the solution does not enter drains or waterways. Contain the spill with a spill kit and dispose of it safely.

I accidentally put AdBlue in my diesel tank. What do I do?

Do not start the vehicle. Depending on how much AdBlue has been put in, this may damage your engine. Empty and clean the tank and discard the mixture removed.

I accidentally put diesel in my AdBlue tank. What do I do?

Again, do not start your engine. Just one drop of diesel will pollute up to 20 litres of AdBlue. Running an engine on contaminated AdBlue will disrupt the SCR system and cause engine failure. To avoid additional damage to your vehicle, contact your vehicle manufacturer, as you may need to replace some AdBlue components.

Is all AdBlue the same?

No. Only buy AdBlue from licensees registered by the VDA. Check for “AdBlue according to ISO 22241” on the container or dispensing system. Not all urea solutions are AdBlue, so be wary of any AdBlue sold at extremely low prices.

* Based on AdBlue consumption of six vol. % of diesel fuel consumption for Euro 5 vehicles, urea-additive CO₂emissions equate to 0.6% or less of diesel fuel CO₂ emissions.

Source: Nationwide Fuels