What is AdBlue and how does it work?

Millions of diesel cars and commercial vehicles use AdBlue to run smoothly. But unlike other fluids commonly associated with combustion engines, AdBlue seems to take a back seat in terms of importance and general understanding.

So to get things back on track, here’s a drive through of everything you need to know about AdBlue. From how it works and how to refill it, to what it’s made from and why it’s needed to keep your vehicle running properly. Let’s get started.

What is AdBlue?

AdBlue is a biodegradable diesel exhaust fluid found in Euro 6 diesel vehicles newly registered from September 2015 onwards.

It works in conjunction with a treatment system called Selective Catalytic Reduction (SCR) to reduce the amount of nitrogen oxide (Nox) leaving your exhaust and entering the atmosphere.

It’s stored in a separate tank either under the bonnet or in the boot, accessed by a blue filler cap (though it can sometimes be a different colour, such as black).

What does AdBlue do?

AdBlue is injected into a vehicle’s exhaust system to turn harmful Nox emissions into water and nitrogen through a chemical reaction in the exhaust system. It consists of chemicals such as urea and deionised water and helps diesel vehicles meet strict emission standards.

How does AdBlue work?

When exposed to high temperature, AdBlue turns to carbon dioxide and ammonia which breaks down harmful NOx emissions produced by diesel engines.

Without AdBlue, a greater amount of harmful chemicals enter the atmosphere and potentially cause respiratory problems as well as smog, acid rain, and other ozone-related issues.

Does my vehicle need AdBlue?

Not every diesel vehicle uses AdBlue technology. It’s mostly found in vehicles manufactured in Germany or France, as well as other makes such as Land Rover and Jaguar registered after September 2015.

As a rule, the more recent the vehicle, the more likely it is to use AdBlue. Other ways to find out if your vehicle uses AdBlue is to check the vehicle handbook or see if there’s an AdBlue filler cap in the boot or under the bonnet. If you’re still unsure, feel free to get in touch.

How do I know when AdBlue levels are low?

If your AdBlue levels run low, a warning light will usually pop up on your dashboard accompanied by a mileage countdown indicator. If you ignore the warning light, your vehicle will eventually switch to reduced power mode or fail to start. Once you’ve refilled to a minimum level, the AdBlue warning light will disappear.

How do I refill my AdBlue tank?

Refilling with AdBlue is as simple as topping up your oil or diesel levels. Simply find the blue filler cap, unscrew it, and top up until the tank is full. If you’re topping up using a bottle, make sure you use the provided funnel or nozzle and avoid mixing it with any other fluid.

Your vehicle handbook will tell you how much AdBlue the reservoir can hold. If you’ve completely run out, it’s typically the case you’ll need a minimum of five litres to safely restart your vehicle. Once you’re finished, wash your hands. AdBlue can cause skin irritation.

Warning: Whatever you do, don’t pour AdBlue in your diesel fuel tank. It will damage a range of components including the fuel tank, pump, and injection system – especially if you start the vehicle.

Where can I buy AdBlue?

You can usually buy AdBlue at a petrol station, garage, or online retailer. Depending on how much you need, there are a range of quantities available from 1.5 to ten litres. If you’re unsure what to buy or how much you need, we can top up your AdBlue levels.

It’s also a good idea to travel with a small container of AdBlue, just in case you run out on the road. They usually come with a nozzle or funnel to make refilling quick and easy.

Get in touch

For more advice about refilling your vehicle with AdBlue, or to book a service or MOT, call us today on 01273 584987.