Our guide explains all you need to know about AdBlue for diesel engines.
AdBlue, or diesel exhaust fluid, is still unfamiliar to some. But if you are in the market to buy a new car (or have already bought one) with a diesel engine that meets certain emissions standards, you might very well need to know what AdBlue is, how to use it, and when to fill up.
What exactly is AdBlue?
AdBlue is a liquid used to reduce the nitrous oxide emissions of diesel engines and is made up of a mixture of urea and deionized water that is sprayed into the exhaust system.
Its widespread introduction coincided with the current Euro 6 emissions standards, which are part of ever more stringent emissions targets that car manufacturers are now required to meet. Without AdBlue, it would be much more difficult to lower the emissions of diesel cars and get them to comply with the latest standards.
AdBlue is normally checked and topped up if needed during a normal car service, but you may need to top it up between services yourself. Nearly all cars that require AdBlue are fitted with a gauge that triggers a warning on your dashboard when you’re running low. It is very important to keep it topped up because modern cars are programmed to not turn on if there’s insufficient AdBlue.
How does AdBlue work?
To comply with Euro 6 regulations, many new diesel-powered cars built since 2006 use SCR technology to inject tiny quantities of AdBlue into the car’s exhaust gases. When this solution combines with exhaust emissions, it breaks down the harmful mono-nitrogen oxides in diesel exhaust. This technology has been used in buses and trucks for a long time, so its effectiveness has been proven.
Which cars use AdBlue in Australia?
Not all new diesel cars need AdBlue and light commercial vehicles (such as dual-cab utes) don’t require the use of it. However, there are popular SUVs and passenger cars that do. These include the Ford Everest, Land Rover Defender, Mercedes-Benz GLE, Volkswagen Touareg and Tiguan, most Audi diesel SUVs, and the Jeep Compass Trailhawk.
Some vans also require AdBlue including the Ford Transit, Fiat Ducato, Mercedes-Benz Vito and Sprinter, and the Volkswagen Multivan and Transporter.
There are new models coming to the market that will also require AdBlue, and some on the market now do. This should be explained by the salesperson but details will also be in the owner’s manual. If in doubt, you’ll spot a separate AdBlue filling cap (which is usually blue) next to where the diesel goes (you do not put AdBlue in the normal diesel tank).
Where to buy AdBlue?
Your AdBlue levels should be checked and topped up at every service and your dealer should refill it at other times when required but this is rarely the cheapest option. AdBlue is also sold at fuel stations although shops such as Repco and Supercheap Auto will likely be the cheapest.
Where can I find an AdBlue pump?
Another option for topping up your AdBlue tank is to use an AdBlue pump. These can be found at most big petrol stations.
An AdBlue pump is usually used by truckers and is often far cheaper and less messy than trying to top-up your tank from a plastic bottle.
Can I refill AdBlue myself?
On several mainstream diesel models, the AdBlue filler is located behind the car’s fuel filler cap. It’s usually smaller than the main fuel filler and will feature a blue cap and markings confirming it should only be used for AdBlue.
If you’re unsure of how to top up your car’s AdBlue, you should refer to the owner’s manual for instructions on how to access the tank – it shouldn’t be difficult. It’s also a good idea to ask the salesperson to show you how to refill the AdBlue during the handover of a new car.
You do not put AdBlue in the normal diesel tank.
What is AdBlue made of?
AdBlue is a non-toxic liquid that’s colourless in appearance and is essentially a solution of water and urea – a substance found in urine. However, in AdBlue, the urea is exceptionally pure and is of a higher grade than that used in cosmetics, glue or fertilisers. Similarly, the water is demineralised, which is far cleaner than water from the tap.
What AdBlue do I need?
When buying AdBlue (Aqueous Urea Solution 32 Diesel Engine Fluid, more simply AUS 32 DEF), you should check it meets the correct specification, so look for the ISO 22241 number on the packaging. This may also appear as ISO-22241-1, ISO-22241-2, ISO-22241-3. This will ensure the AdBlue doesn’t damage your car’s SCR catalyst – a costly repair.
Assuming your AdBlue meets these specifications, one brand of AdBlue should be pretty much the same as another, in the same way that diesel fuel is fundamentally the same from one retailer to another. Further, the Australian Competition and Consumer Commission (ACCC) stipulates that manufacturers cannot mandate the use of genuine parts and consumables – as long as it is designed for that car.
How many kays does AdBlue last?
There is no set length you can expect AdBlue to last for, but 10 litres is usually go for around 10,000km.
I have an AdBlue warning light. What should I do?
All diesel cars that use AdBlue will give you plenty of warning if you’re running low. You’ll usually be alerted with a dashboard warning before running out, along with an amber warning light. This warning will remain on every time you restart your car until the AdBlue levels have been topped up to the desired level.
If you don’t top up the AdBlue before it gets too low you could find yourself with a problem. This is especially problematic for those traveling in remote areas. Vehicle manufacturers that require AdBlue to meet emissions standards program the car to not turn on if there isn’t sufficient AdBlue in the tank – so keep it topped up and consider bringing some with you on long trips.
Does AdBlue affect fuel consumption?
Manufacturers have yet to release any data to suggest that Adblue has an adverse effect on fuel consumption. Economy figures for a new diesel car on sale in Australia will factor in any effect from the use of AdBlue in any case.
Developments in engine technology, changes to the way economy figures are calculated and a range of other variables means it’s essentially impossible to find differences in fuel consumption between new and older cars and attribute them solely to the use of AdBlue.
What happens if you run out of AdBlue?
Ignoring the AdBlue warning light on your dashboard is not advised under any circumstances. If you run out of AdBlue while driving, your car’s performance will likely be affected as it tries to reduce its emissions output by going into ‘limp mode,’ reducing the speed at which you can drive and sometimes turning off your vehicle’s stereo or air conditioning to preserve power.
Once you’ve stopped, the majority of modern cars cannot be restarted while the AdBlue tank is completely empty.