AdBlue is a non-toxic, colorless liquid made of 32.5% urea and 67.5% deionized water.It's used in diesel vehicles equipped with Selective Catalytic Reduction (SCR) systems to reduce harmful nitrogen oxide (NOx) emissions. When injected into the exhaust stream, AdBlue reacts with NOx gases in the SCR catalyst and converts them into harmless nitrogen and water vapor.
How Does AdBlue Affect a Vehicle?
AdBlue does not directly affect engine performance. It works solely with the exhaust system to clean emissions. However, modern diesel engines with SCR systems are programmed to rely on AdBlue; without it, the vehicle may not start or may go into limp mode to reduce emissions.
Which Cars Use AdBlue?
AdBlue is used in many modern diesel vehicles, including cars, vans, trucks, and buses. Brands like Audi, BMW, Mercedes-Benz, Volkswagen, Ford, Peugeot, Renault, and many others use AdBlue technology in their diesel engines.
When Did Cars Start Using AdBlue?
The widespread use of AdBlue in passenger cars started around 2014–2015, mainly due to the introduction of stricter Euro 6 emission standards in the European Union. Heavy-duty vehicles had already been using SCR and AdBlue since the mid-2000s to comply with Euro IV and V standards.
Common Problems Related to AdBlue Systems
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Freezing: AdBlue freezes at -11°C. Although systems are designed with heaters, freezing can still be problematic in cold climates.
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Crystallization: Spilled AdBlue can crystallize and block pipes or injectors if not cleaned properly.
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Sensor or Pump Failure: The AdBlue tank has sensors and a pump that can fail, leading to warning lights or engine start restrictions.
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Contamination: AdBlue must be pure. Contamination with other fluids can damage the SCR system.
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Running Out of AdBlue: If the AdBlue tank is empty, most vehicles will not restart after turning off the engine.
Maintenance and Refilling
AdBlue consumption depends on driving style and vehicle type, typically around 1–3 liters per 1,000 km. Many cars have a separate AdBlue filler near the diesel cap or in the trunk. A warning light will appear when the fluid is low. Only certified AdBlue fluid should be used.
Regulatory and Environmental Impact
AdBlue enables diesel vehicles to meet stringent emission regulations, particularly Euro 6 in Europe. It plays a crucial role in reducing urban air pollution caused by NOx emissions. However, some manufacturers and users have tampered with AdBlue systems to bypass emissions controls, leading to legal and environmental consequences.
In Summary
AdBlue is essential for modern diesel vehicles to meet environmental standards. While it doesn’t affect how a car drives, its presence is mandatory for proper function in vehicles with SCR systems. Understanding its role, maintenance needs, and possible issues is key to ensuring long-term reliability and compliance with emissions laws.
