What is Ad Blue?

March 1, 2019
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What is AdBlue?

AdBlue is an exhaust fluid, not a fuel additive. It's stored in a separate tank and is topped up via a blue filler cap located next to your fuel cap.

AdBlue is a colourless, non-toxic mixture of urea and de-ionised water. It’s not actually blue.

How does Adblue work?

Tiny amounts of AdBlue are pushed into the flow of the exhaust. At very high temperatures AdBlue turns to ammonia and carbon dioxide.

Inside the SCR (Selective Catalytic Reduction) catalyst, harmful nitrogen oxide in the exhaust reacts with the ammonia and is transformed to harmless nitrogen and water.

Similar technology has been used for years in buses and heavy lorries.

What happens if I run out of Adblue?

If you run out of AdBlue while driving, the engine’s power and performance will be reduced to limit the emissions produced. Once you’ve stopped, you won’t be able to restart the engine if your AdBlue tank is empty.

The car will give you plenty of warning that the AdBlue tank is running low. You'll usually see a text warning on the dashboard at around 1500 miles to go followed by an amber warning light.

Is it safe to drive with the Adblue warning light on?

It’s not a major safety issue, but if you don’t top up, you’ll eventually run out of AdBlue and you won’t be able to start the car.

When the warning light first comes on you’ll have plenty of time to top up – so don’t panic. Give Prestige Cars Kent Service Centre a call 01689 664 769 and we can book you in for a top up for just £25 including VAT.