How to check, refill and top up AdBlue

What does AdBlue do?

AdBlue is a trade name for a DEF injected into the exhaust system automatically to reduce harmful NOx exhaust emissions. Many cars will display an Adblue technology warning light, the meaning of which must be heeded, by consulting the handbook. When considering how much AdBlue is used driving technique plays a big part. A rough guide is 1.5 litres of AdBlue to be consumed every 600-1,000 miles.

Yet, the motor repair trade has alerted us of issues with the system, fitted to diesel cars, which we hope to alleviate with the following advice.

Top tips:

1. Do not pour AdBlue into the diesel fuel tank. The car doses AdBlue into the exhaust, not the fuel. To top up the level, familiarise yourself with the location of the separate AdBlue tank and its filler. The picture shows a system, where the tank is topped-up from the engine bay.

2. Ask yourself, 'How long does AdBlue last – does AdBlue go out of date?' The answer to the latter is yes - 6-12 months being a general guide. Never use AdBlue after the expiry date on the label has passed and, unless you cover very high mileages, do not stockpile large quantities.

3. Ultra-violet light speeds up AdBlue’s deterioration and expired fluid damages your exhaust system’s delicate catalyst. Therefore, buying bottles that have been sitting outside a petrol forecourt may not be a good idea and could cause AdBlue problems. Instead, look for bottles that have been stored indoors, or in the dark.

4. Do not ignore AdBlue refill messages. The engine may stop running and might not start again, even after you have refilled the AdBlue tank. It may not be possible to reset the AdBlue warning without professional diagnostic equipment.

5. Can you overfill the AdBlue tank? Yes. This situation can create a vacuum inside the tank that prevents the AdBlue from being injected into the exhaust initially and this could cause the AdBlue light to remain on after filling. In some diesel vehicles, the AdBlue pump and circuitry are located on top of the tank, so overfilling risks moisture contamination that can damage the circuits. If you need to find out how much the Adblue cost that a car uses, consult its handbook.

Keep up to date with GEM Motoring Assist at:

Twitter: @motoringassist

Facebook: @gemmotoringassist

Instagram: @gem_motoringassist

LinkedIn: @gem-motoring-assist-limited

Share this on socials below: