{"id":105008,"date":"2021-06-30T14:09:17","date_gmt":"2021-06-30T13:09:17","guid":{"rendered":"https:\/\/www.crownoil.co.uk\/?page_id=105008"},"modified":"2026-01-12T13:27:38","modified_gmt":"2026-01-12T13:27:38","slug":"adblue-guide","status":"publish","type":"page","link":"https:\/\/www.crownoil.co.uk\/guides\/adblue-guide\/","title":{"rendered":"What is AdBlue\u00ae and How Does it Work?"},"content":{"rendered":"\n
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What is AdBlue\u00ae<\/sup>?<\/h2>\n\n\n\n

AdBlue\u00ae<\/sup><\/a>, the common term for NOx reduction agent AUS 32 diesel exhaust fluid (DEF), is a necessary fluid for all modern diesel engines that neutralises pollutants released from diesel fuel combustion. The name AdBlue\u00ae<\/sup> is a trademarked term held by the German Association of the Automobile Industry (VDA<\/a>)<\/p>\n\n\n\n

As a UK-leading AdBlue\u00ae<\/sup> supplier, our experts have rounded up everything there is to know about the diesel exhaust fluid to ensure you are using it correctly. If you still have questions after reading this guide, give our experts a call on 0330 123 1444<\/a>.<\/p>\n<\/div>\n\n\n\n

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What does AdBlue\u00ae<\/sup> do?<\/h2>\n\n\n\n

Since 2015, AdBlue\u00ae<\/sup> has been required by law for use in modern diesel engines to reduce harmful nitrous oxide (NOx) emissions that cause acid rain.<\/p>\n<\/div>\n\n\n\n

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What is AdBlue\u00ae<\/sup> made from?<\/h2>\n\n\n\n

The liquid is made up of a mixture of urea and deionised water that’s sprayed into the exhaust system<\/p>\n\n\n\n

There are two ways of achieving a reduction in NOx that forms from the combustion of diesel fuel: through a selective catalytic reduction (SCR) system and through exhaust gas recirculation. If your vehicle uses the selective catalytic reduction system, then you\u2019ll need AdBlue\u00ae<\/sup>.<\/p>\n<\/div>\n\n\n\n

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What emission regulation mandates AdBlue\u00ae<\/sup>?<\/h2>\n\n\n\n

From September 2015, all diesel vehicles registered in EU member states must meet Euro 6 emission standards<\/a>, which aim to reduce the nitrogen oxide emissions produced. AdBlue\u00ae<\/sup>is a legal requirement in diesel vehicles manufactured after this date to ensure they meet these standards.<\/p>\n<\/div>\n\n\n\n

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How long does AdBlue\u00ae<\/sup> last? How much will I need?<\/h2>\n\n\n\n

As AdBlue\u00ae<\/sup> is a diesel exhaust fluid, it\u2019s used at a much slower rate than your fuel, so it lasts a lot longer than the diesel in your fuel tank – around a rate of 5% to diesel fuel is a rule of thumb worth following.<\/p>\n\n\n\n

As a guide, the table below illustrates how much AdBlue\u00ae<\/sup> fluid you can expect to use for various vehicle sizes that consume different amounts of diesel per week. This should help you calculate how long it will last.<\/p>\n<\/div>\n\n\n\n

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Diesel consumption per week<\/strong><\/td>Estimated weekly AdBlue\u00ae<\/sup> consumption of each vehicle size in litres<\/strong><\/td><\/tr><\/thead>
 (Litres)<\/strong><\/td>Light (<18 tonnes)<\/strong><\/td>Medium (18-35 tonnes)<\/strong><\/td>Heavy (35+ tonnes)<\/strong><\/td><\/tr>
1000<\/strong><\/td>30<\/td>50<\/td>60<\/td><\/tr>
2500<\/strong><\/td>75<\/td>125<\/td>150<\/td><\/tr>
5000<\/strong><\/td>150<\/td>250<\/td>300<\/td><\/tr>
7500<\/strong><\/td>225<\/td>375<\/td>450<\/td><\/tr>
10000<\/strong><\/td>300<\/td>500<\/td>600<\/td><\/tr>
15000<\/strong><\/td>450<\/td>750<\/td>900<\/td><\/tr>
20000<\/strong><\/td>600<\/td>1000<\/td>1200<\/td><\/tr>
25000<\/strong><\/td>750<\/td>1250<\/td>1500<\/td><\/tr>
35000<\/strong><\/td>1050<\/td>1750<\/td>2100<\/td><\/tr>
50000<\/strong><\/td>1500<\/td>2500<\/td>3000<\/td><\/tr><\/tbody><\/table><\/figure>\n<\/div>\n\n\n\n
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How does AdBlue\u00ae<\/sup> work?<\/h2>\n\n\n\n

In order to work in an engine, AdBlue\u00ae<\/sup> is filled into a designated tank on the vehicle with its own gauge and sensor system. The fluid is used in the selective catalytic reduction system, where it’s sprayed onto the exhaust fumes soon after combustion and works by catalysing the breakdown of nitrous oxides into harmless nitrogen gas and water.<\/p>\n<\/div>\n\n\n\n

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How does the selective catalytic reduction (SCR) system work?<\/h2>\n\n\n\n

Diesel combusts within an engine, and as it does this, it is forced through the exhaust system and expelled out into the air that we breathe. Because petroleum products have trace impurities such as sulphur and nitrogen that occur in crude oil and are still present after it is refined, the high pressure and temperature of the engine allow for the formation of NOx particles.<\/p>\n\n\n\n

With the use of AdBlue\u00ae<\/sup>, harmful exhaust gases are treated before they\u2019re released. The fluid is sprayed into the exhaust system, where it reacts with the gases, and the selective catalytic reduction catalyst breaks them down into harmless nitrogen and water vapour. Once that\u2019s done, all that\u2019s left is nitrogen, water and CO2<\/sub> to be expelled from the exhaust system.<\/p>\n<\/div>\n\n\n\n

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\"Adblue<\/figure>\n<\/div>\n\n\n
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The image shows AdBlue\u00ae<\/sup>‘s nitrous oxide reduction in action.<\/em><\/strong><\/p>\n<\/div>\n<\/div>\n\n\n\n

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Tips for Buying & Using AdBlue\u00ae<\/sup><\/h3>

Learn how you can get the most out of your AdBlue\u00ae<\/sup><\/p><\/div>Read more<\/span><\/a>\n\n\n\n

Latest AdBlue\u00ae<\/sup> Prices<\/h3>

Learn how you can save on your AdBlue\u00ae<\/sup> costs<\/p><\/div>Read more<\/span><\/a>\n<\/div>\n<\/div>\n\n\n\n

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Physical and chemical properties of AdBlue\u00ae<\/sup><\/h2>\n\n\n\n

In order to be used in diesel engines, AdBlue\u00ae<\/sup> must meet the ISO 22241 specifications<\/a>. It’s a colourless liquid with a slight ammonia odour that freezes at -11\u00b0C and boils at 100\u00b0C.<\/p>\n\n\n\n

In terms of chemical properties, AdBlue\u00ae<\/sup> is alkaline, with a pH between 9 and 10 and has a density of 1.088g\/cm3<\/sup>. AdBlue\u00ae<\/sup> that meets specifications for use in diesel engines must have a water solubility of 100g\/litre and a urea content<\/a> of between 31.8% and 33.2%.<\/p>\n\n\n\n

To learn more about the properties that BS 22241 diesel exhaust fluid must meet, view the AdBlue\u00ae<\/sup> specifications<\/a>.<\/p>\n<\/div>\n\n\n\n

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Why use AdBlue\u00ae<\/sup> that meets the specifications?<\/h2>\n\n\n\n

Using the diesel exhaust fluid that meets specifications is essential because low-grade DEF will contain impurities that will harm the selective catalytic reduction system in your hardware, and result in it working ineffectively and allowing your engine to release harmful gases into the atmosphere.<\/p>\n<\/div>\n\n\n\n

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AdBlue\u00ae<\/sup> manufacturing and handling specifications<\/h2>\n\n\n\n

The manufacture and handling of AUS 32 diesel exhaust fluid falls within the ISO 22241 standards. The following international standards are utilised within our strict manufacturing and handling processes<\/p>\n<\/div>\n\n\n\n

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