You may wonder what AdBlue is. If you drive a newer diesel car with an AdBlue tank then you will already be familiar with this liquid which isn’t actually blue at all.

So, what is AdBlue?

AdBlue is a colourless, non-toxic exhaust fluid. It’s certainly not a fuel additive. It reduces harmful emissions and is stored in a separate reservoir with a (usually) blue filler cap located either next to your fuel filler, in the boot or under the bonnet. An increasing number of diesel vehicles, typically those with larger engines, are being fitted with AdBlue tanks.

However, certain manufacturers may refer to it simply as ‘Emissions Additive’.

How does it work?

In a nutshell, small amounts of AdBlue are injected into the flow of exhaust gases and at high temperature, through a chemical process, it turns the Nitrogen Oxide (NOX), Carbon Monoxide (CO) and Hydro Carbon (HC) into harmless nitrogen, water and CO2. This reduces any harmful gases released into the environment.

What happens if it runs out?

Quite simply, your engine’s power will drop to limit the emissions. Not ideal if you get caught out on a motorway. Once at a standstill, if the AdBlue tank is empty, you won’t be able to restart your engine. However, you will be warned of this well in advance, so don’t ignore any mileage countdowns or warning lights that appear on your dash.

Does my car use Adblue?

Not all manufacturers use this technology. If you own a diesel from Jaguar, Land Rover or any German or French brand and it was registered after 2015, then it’s very likely. You can check:

• Your car’s Handbook
• If there is a blue filler cap with Adblue on it
• If the model contains ‘Blue’ or ‘SCR’ in the name
• By calling our team for advice

Proceed with caution

Mistakes with AdBlue can lead to costly rectification work. It must NEVER be added to fuel nor should fuel ever be added to the AdBlue tank. If you do, never start the car but call your breakdown service who can recover it to your local service centre. Lastly, it is the driver’s responsibility to ensure they top up in between servicing with the correct brand of AdBlue. Cheap, nasty alternatives bought on the go at petrol filling stations can wreak havoc with the system and cost hundreds of pounds to put right. We always fit the specific manufacturer’s product when servicing, make sure you do the same in between services or you could be faced with hefty repairs.