What is AdBlue?

Advanced emissions control for diesel engines.

Owners of modern diesel vehicles, such as Volkswagens, will have noticed a blue AdBlue® cap next to their diesel cap, along with other references to AdBlue throughout the dashboard and media system. While a Volkswagen vehicle will let you know when your AdBlue needs to be topped-up, and your service technician will include it as part of your service when needed, it can be helpful to know exactly what AdBlue is and how it’s helping your vehicle to reduce its effect on the environment.

Some Volkswagen TDI models are fitted with AdBlue® emissions control equipment which cleans exhaust gases helping cars to comply with the new EU6 exhaust emissions regulations.

It’s a non-toxic, non-flammable; biodegradable urea and water-based liquid additive that processes the gases in a car exhaust system to remove harmful nitrogen oxide (NOx) emissions. AdBlue solution is stored in a tank positioned near the car’s conventional fuel tank, accessed through a cap usually found at the rear of the car; its location will depend on the model (it’s right next to the diesel fuel filler cap in the new Volkswagen Passat TDI, for example).

How do I know if my car uses AdBlue?

A quick visual check will reveal whether your diesel vehicle uses AdBlue. You should find an AdBlue filler cap next to your diesel cap in your Passat, Tiguan, or Amarok, or in the boot in other diesel Volkswagen vehicles. You may also find a ‘kilometres to refill’ message in your multi-function display.

The size of the AdBlue tank fitted to your car will vary depending on which model you have, therefore the intervals between top ups will vary. Other factors such as mileage covered, journey types, driving styles and environmental conditions can also influence how much AdBlue is consumed. As a guide, a passenger car will consume approximately 1.5-2.5 litres of AdBlue approximately every 1,000km.

AdBlue cap next to fuel cap or in the boot
Cars consume around 1.5l per 1,000km

How does AdBlue reduce emissions?

Reduced raw exhaust emissions are achieved in TDI engines equipped with AdBlue through an advanced, modified fuel injection system, exhaust gas re-circulation and optimised turbocharging.

The Volkswagen low emission system uses a DeNOx catalyst, diesel particulate filter and injection of AdBlue.

The AdBlue solution is stored separately from the fuel tank and is pumped in small quantities into the exhaust pipe ahead of the DeNOx catalyst when the engine is running.

The quantity of AdBlue injected depends on a number of factors, such as your driving style, engine loading and atmospheric conditions.

Exhaust gas recirculation
Optimised turbocharging

How to refill the AdBlue in your vehicle

A dash message will inform you if the AdBlue reservoir is running low (as shown above). It is important to note that the engine will not run if the AdBlue supply is exhausted. AdBlue consumption often increases when driving with a load (exacerbated by high engine load driving, or towing a trailer or caravan), with the result that the low AdBlue message may deploy earlier than usual.

Refill the AdBlue tank with 1.89-litre refill containers of AdBlue which are available from our Parts department. This will help to ensure that you are only using the AdBlue approved by Volkswagen in accordance with the Volkswagen standard.

To refill the tank, a fill adaptor must be screwed onto the AdBlue refill container (the adaptor comes complete with the refill tank). By applying pressure to the bottle, the valve in the fill adaptor opens, allowing the AdBlue solution to flow through and fill the tank. This process is demonstrated in the video above.

Tip: We can fill the AdBlue tank for you. Mention this with your next service or drop-by when you’re next in town.

AdBlue® is a registered trademark of the German Association of the Automotive Industry (VDA).