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What’s AdBlue, and does my car need it?

Never come across the term AdBlue? Don’t worry, you’re not alone. But if you drive a diesel car – especially a newer model – it may be something you’ll need to have on your radar. Here’s the lowdown.

Never come across the term AdBlue? Don’t worry, you’re not alone. But if you drive a diesel car – especially a newer model – it may be something you’ll need to have on your radar. Here’s the lowdown.

Written by
Julie Daniels
Motor insurance comparison expert
29 DECEMBER 2020
5 min read
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What is AdBlue?  

AdBlue is an exhaust fluid. It’s used in modern diesel cars to lower their emissions, via an AdBlue tank separate to your main fuel tank.

What does AdBlue do?

AdBlue reduces nasty emissions from diesel cars. This allows car manufacturers to meet their emissions targets, and means that you get extra peace of mind.

Who needs AdBlue?

If you own a recent diesel car, or a van fitted with Selective Catalytic Reduction (SCR), chances are you’ll have already come across AdBlue. It’s used widely in diesel vehicles produced after 2015.

How does AdBlue work?

When you drive, your car injects small amounts of AdBlue into the exhaust. This produces ammonia, which reacts with the nitrogen oxide (that’s the bad stuff) produced by the exhaust. The harmful nitrogen oxide then turns into nitrogen and water – both harmless substances that occur naturally anyway.

How harmful are exhaust emissions?

Nitrogen oxide – otherwise known as NO2 – forms when diesel burns at high temperatures. NO2 pollutes our air and can lead to serious health problems, including asthma, heart disease and strokes.

That’s why there are laws limiting how much NO2 your car can emit. AdBlue reduces your emissions, helping keep your car in line with the rules.

Where can you get AdBlue?

Wondering where to buy AdBlue? It’s easy to get hold of online. You’ll usually be able to find trusted vendors on sites like Amazon and eBay, as well as specialist car websites.

If you don’t have time to wait for an online delivery, you can always pick some up from your local garage or petrol station.

How much is AdBlue?

AdBlue isn’t especially expensive – you should be able to pick up 10 litres from around £10. Prices do vary though, so it’s definitely worth shopping around first.

Do I need to refill AdBlue myself?

How often you’ll need to refill your AdBlue tank will depend on a few factors – not least the size of your tank, and how far you drive.

Roughly speaking, you’ll be able to do 600 miles on 1-1.5 litres of AdBlue. If your tank holds 20 litres, that will mean you can travel some 12,000 miles on just one tank. But many tanks are much smaller than 20 litres. If yours is only five litres, you’ll need to refill it sooner.

Your mechanic should top up your AdBlue supply when you take your car in for a service. If you’re not the kind of driver who racks up loads of miles, you may well find that’s plenty.

But if you’re a long-distance driver, you’ll need to top it up yourself between services. To find out how, check your user handbook.

Where do I find the AdBlue tank?  

AdBlue is kept in a reservoir tank separate to your fuel tank. It’s usually right next to the fuel tank, so you shouldn’t have any trouble finding it. If you can’t see yours, check your manufacturer’s handbook.

Can I put AdBlue in my fuel tank?  

Don’t do it! You could end up causing serious damage to your fuel tank. If you do it by mistake, then avoid turning on the ignition.

Help! I already put AdBlue in my fuel tank. What should I do?

Don’t worry – all’s certainly not lost. Just call out your breakdown service. They’ll drain your fuel tank and dispose of the AdBlue. Depending on what insurance you have, you may find that you’re covered.

What is AdBlue made of?

AdBlue is made from a combination of de-ionised water and urea. Urea is a substance found in urine and, because of this, a rumour went around that AdBlue is made from pig’s urine. Thankfully, this couldn’t be further from the truth. AdBlue is a man-made liquid that’s totally non-toxic and sterile. Granted, it doesn’t smell great, though…

Will AdBlue affect my fuel consumption?

Not that we know of. Certainly, no one’s come up with any data to suggest that using AdBlue will be detrimental to your fuel consumption.

How long does AdBlue last?

How long your AdBlue lasts will depend on a few things, like the size of your tank and how far you drive. How fast you drive will also have an effect.

But in an average, family sized car, the general rule is that a litre of AdBlue will last roughly 600 miles.

What happens if I run out of AdBlue?

You don’t want to run out of AdBlue, as your car probably won’t start again until you refill the tank. Car manufacturers do this deliberately to stop people driving around with illegally high exhaust emissions.

How do I know if I’m running out of AdBlue?

There should be a dashboard warning light that lets you know if your AdBlue supplies are running low. Make sure you don’t ignore any warnings, as if you run out completely, you won’t be able to start your car.

What cars use AdBlue?

HGVs like trucks, buses and coaches have been using AdBlue since way back. As for cars, it’s generally used in models built after 2015.

Does my car use AdBlue?

AdBlue’s been a mandatory requirement since 2017, so if your diesel car is newer than that, it’ll definitely use AdBlue. If you’re not sure, you can always double check in your manufacturer’s handbook.

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