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Tips for Buying and Using Quality AdBlue

Operate a fleet of diesel engine vehicles, such as a heavy goods vehicle (HGV)? Learn more about AdBlue below

With all modern diesel engine vehicles such as heavy goods vehicles (HGVs) now required to use a process called selective catalytic reduction (SCR), finding a reliable supplier of AdBlue for your business is of utmost importance.


What is AdBlue?

AdBlue is an exhaust fluid, not to be confused with a fuel additive, and is the most recognised form of Diesel Exhaust Fluid (DEF), although it’s a trade name registered by the German car manufacturer’s association.

The most recent emissions legislation (Euro 6) introduced in 2014 saw the use of AdBlue becoming mandatory to help minimise nitrogen oxide emissions released from diesel engines. In order to be used in diesel engines, AUS32 diesel exhaust fluid needs to meet ISO 22241 specifications.

What is AdBlue made of?

AdBlue is a non-toxic, odourless mixture made up of deionised water (67.5%) and urea (32.5%), which is where it gets its official name from (AUS32, Aqueous Urea Solution 32.5%).

Many people think AdBlue is made of pig urine – but we can assure you it is not! Urea is a compound in nitrogen that turns into ammonia when heated. It’s technically derived from a by-product of urine but it is synthetically made for mass production.

Although its name insinuates that AdBlue is blue, it is in fact colourless.

What does AdBlue do?

AdBlue is needed to meet legal emission standards to improve public health and reduce the UK’s overall emissions footprint. Beyond the legal requirements of its usage, AdBlue also helps to reduce the number of harmful pollutants released from diesel-engine vehicles. This, of course, is beneficial for any business aiming to reduce its own carbon footprint, as well as helping to protect the environment. Here at Crown Oil, we’re doing all we can to reduce our own carbon footprint.

As the UK’s largest sole contributor of greenhouse gases, it’s no surprise that the transport sector is under increasing pressure to reduce pollution levels.

Where does AdBlue go?

Our Adblue diesel exhaust fluid (DEF) comes in secure packaging with clear instructions on how to use it. There should be a specified tank on your vehicle for topping up the DEF tank with the AdBlue solution.

AdBlue is stored in a separate container and is topped up using a blue filter cap located either next to your fuel filler, under the bonnet or in the boot. Your vehicle’s handbook will include any fitted AdBlue technology and how to add it safely.

The SCR system in your vehicle is very sensitive, so care must be taken because if anything other than diesel exhaust fluid in that tank, you risk damaging the vehicle.

Even water can damage the SCR system on your vehicle, so it’s not advisable to water down your AdBlue additive if you find you’re running low. If your SCR system is damaged, it can be very expensive to repair it, so it is important to be cautious when handling your AdBlue and top-up your vehicles.

How does AdBlue work?

AdBlue reduces harmful emissions through a process called Selective Catalytic Reduction (SCR). Diesel never actually comes into contact with AdBlue as both fluids are stored separately, which is also known as after-treatment technology, allowing the manufacturer to build as much power as they want.

Before emissions are released, AdBlue is sprayed on the exhaust fumes after combustion, where the aqueous urea is converted into ammonia and CO2. This breaks down harmful mono-nitrogen oxides in the exhaust, leaving nitrogen and water which are released into the atmosphere through the exhaust system.


What happens if I run out of AdBlue?

Vehicles give plenty of warning when AdBlue is running low in the tank, usually via an alert on the dashboard. If your tank runs dry while you’re driving, the engine’s power and performance will drop to limit emissions.

Once the engine has stopped, it won’t restart until the tank has been topped up.

Which vehicles use AdBlue?

If you have a diesel vehicle from Land Rover, Jaguar or any German or French manufacturer and it was registered after September 2015, it will use AdBlue. Engines with over 1.6-litre capacity will in almost all instances feature AdBlue technology. Without this, many diesel cars would not meet new strict emission regulations.

However, some older vehicles also use AdBlue, so it’s always best to check:

  • the vehicle handbook
  • if there’s an AdBlue filler cap
  • if the model name contains SCR or Blue
  • with your dealer

How long does AdBlue last?

Only a small amount of AdBlue is used every journey and a full tank is likely to last you several thousand miles. However, AdBlue consumption depends on the engine and how economically you drive. It is usually around 1 litre every 600 miles, but some vehicles use as much as 1 litre every 350 miles.

Most drivers will fill up their AdBlue tank at least once between services. Our guide to AdBlue gives a more in-depth estimate of how much diesel engine fluid vehicles will use.

What is the shelf life of AdBlue?

If AdBlue is stored at ambient temperatures of around 24 degrees Celsius, it will last around two years. But if it’s subject to temperature fluctuations, its lifespan will decrease to around 1 year.

Is AdBlue dangerous?

No, it’s completely harmless to humans, but it can corrode bodywork if spilled, so it’s important to take care when transporting and topping up your tank.

Will AdBlue freeze?

The standard 32.5% solution will begin to crystalise and freeze at -11.111oC. When mixed, urea and water free at the same rate, so when the fluid thaws, it does not become diluted or overly concentrated, therefore having no impact on the grade of the product.

Can I add antifreeze to AdBlue to prevent it freezing?

DEF is a specific formulate of 32.5% urea and water, but it also contains other compounds in minute quantities to stabilise it. Adding additives would affect the precise chemical makeup and therefore reduce the NOx reducing properties. Any additional blending will compromise its ability to work properly and potentially harm the SCR system.

Are AdBlue emulators illegal?

Yes, AdBlue emulators effectively allow a vehicle to run without a working SCR system, tricking the engine and therefore breaking the law. These devices deactivate the warning light on a vehicle’s dashboard that alerts the driver that the diesel exhaust system is not working.

AUS32 is an effective way to help the industry in its efforts to reduce its environmental impact, so it’s alarming that an increasing number of transport operators are illegally using these cheat devices to disable pollution control systems.

During random roadside tests carried out between August 2017 and February 2018, the Driver and Vehicle Standards Agency (DVSA) found that of the 10,237 trucks checked, 293 contained a cheat device that switches off the use of AdBlue.

Why are transport operators using AdBlue emulators?

Using the diesel exhaust fluid is an added running cost for operators – especially those who travel long distances. Disabling AdBlue saves companies around 5% of costs, but increases emissions by almost 2.5 times the safe level.

Tips for safely using and handling AdBlue

  • The diesel exhaust fluid tank on your vehicle is clearly marked
  • You can never be certain of the quality of a product with a similar name. So make sure you always buy AdBlue from a reputable supplier
  • When you need to refill, only use equipment that’s designed for diesel exhaust fluid
  • Always close the AdBlue tank cover firmly after refilling
  • Diesel exhaust fluid will start to freeze at -10°C but it can be used when it has thawed.
  • If you need to clean your AdBlue container, use demineralised water
  • Use water to clean any AdBlue that has spilt on surfaces, inside your vehicle or even on the ground
  • Storing AdBlue in direct sunlight will damage the quality of it
  • Your tank which holds white diesel fuel is not designed for AdBlue so make sure you don’t mix the tanks up
  • Putting anything other than AdBlue in the AdBlue tank can be damaging and expensive to repair
  • Other fluids cannot be mixed with AdBlue – not even water, as it will damage the SCR.
  • If you think water or any other fluid has got into your AdBlue, do not use it and call us on 0330 123 1444 for advice.

Where can you buy AdBlue?

Buying cheaper AdBlue may help to reduce costs initially, but it can actually leave you with expensive problems in the future, including:

  • Higher pollution levels
  • Pressure build-up
  • Decreased fuel economy

You can buy DEF at most petrol stations and from Crown Oil. As a nationwide AdBlue supplier with vast buying power, we can offer huge savings on your AdBlue, and deliver it directly to your site – simply call us for the latest AdBlue prices. Alternatively, if you’re in the area, you can pick it up from one of our oil depots.

We also have a vast range of ancillary products and dispensing equipment on hand, such as hand pumps, IBC dispensers and drip trays to avoid contamination and spills.

If you have any further questions about AdBlue that we haven’t answered here, you can call 0330 123 1444 or request a quote by filling in the online form on this page.

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