What Is AdBlue And Do You Need It?

Most modern diesel cars require AdBlue to function. Our guide explains what AdBlue is and why your diesel car may need it, and when you should refill it.

What is AdBlue?

AdBlue is a diesel exhaust fluid that is used in vehicles equipped with Selective Catalytic Reduction (SCR) technology to reduce emissions of oxides of nitrogen (NOx). It is injected into the exhaust stream and helps to break down Nitrogen Oxide (NOx) into harmless nitrogen and water vapour.

Neither fuel nor an additive, AdBlue is a non-toxic, biodegradable and non-flammable solution made of urea and water. It was introduced to meet the Euro 6 Emissions Standards which were made mandatory for new vehicles in September 2015.

Does my car need Adblue?

If you have a diesel car that was manufactured around the year 2015, then it is likely it will need Adblue. You should only use AdBlue on diesel vehicles equipped with SCR systems, so consult your vehicle’s manual if you have any doubts.

Diesel car brands manufactured after September 2015 such as Peugeot, Citroën, Renault, Opel, Mercedes, Volkswagen, BMW, and Audi will most likely be equipped with SCR technology and hence will need AdBlue.

What happens if I do not use AdBlue for my diesel car?

If a vehicle is driven without AdBlue, the exhaust emissions will no longer meet the latest standards and the vehicle will eventually stall or sometimes even fail to start. In some cases the engine management system will reduce engine power to protect it, and in other cases the engine will stop and not restart until AdBlue is added.

What happens if my AdBlue runs out?

Adblue level indicator on dashboard

If your AdBlue runs out and you continue to drive your vehicle, the engine will eventually shut down. This is a safety measure to prevent any further damage to your engine.

The best way to prevent this from happening is to refill AdBlue when the warning message appears on the dashboard, usually with a range of 1,490 miles to go.

What does the AdBlue warning light look like?

The AdBlue warning light differs depending on the manufacturer so it’s advisable to check the vehicle handbook to see what it looks like for your car. Alternatively, this infographic may help you identify what it looks like.

Can I refill AdBlue myself?

Usually, AdBlue is usually refilled during a routine service on your vehicle. However, if you need to refill yourself in between services, it’s fairly easy to do so. Keep in mind that you need to be careful as AdBlue is corrosive and can cause damage to your skin as well as your vehicle’s paintwork.

The AdBlue refill bottle usually comes with a spout that plugs into the car’s AdBlue filler cap. Check your vehicle handbook to confirm that the location of the AdBlue cap is accessible (it is usually blue in colour and is next to the fuel cap). Once you locate it, simply pour in the AdBlue to top it up.

I have a diesel car which uses AdBlue. Can I drive it in Europe?

If your car uses AdBlue you can normally drive it in Europe (provided it also meets other regulations of course). Most modern Euro 6 models are allowed in most cities across Europe.

What is the cost of AdBlue?

Most retailers have AdBlue available for approximately £10 for 5 litres. Main dealers usually charge slightly more per litre.

What about if you put AdBlue in the fuel tank?

Fuel filler and diesel filler caps

If you put the Adblue in the fuel tank or you put the diesel in the AdBlue tank, DO NOT start the engine as this can cause damage to the engine. If this happens, seek professional advice from a garage or qualified technician.

Does AdBlue go out of date?

Just like many other fluids in a vehicle, AdBlue can go bad over time. If a vehicle is sitting for a long time, the AdBlue system can start to break down and become less effective.

In case you have leftover AdBlue, keep in mind it degrades over time so make sure to keep it in a temperate environment and out of direct sunlight.

If you ever need a car repair or service for your diesel car, ClickMechanic is here to help. Simply enter your vehicle registration number and postcode and get a fixed upfront price.