An AdBlue system is part of a vehicle’s Selective Catalytic Reduction (SCR) technology, used in diesel engines to reduce harmful nitrogen oxide (NOx) emissions.

Here’s how it works

AdBlue, a solution of urea and deionized water, is stored in a separate tank in the vehicle.

The system monitors the level of AdBlue in the tank and alerts the driver when it needs to be refilled.

As exhaust gases leave the engine and pass through the exhaust system, a small amount of AdBlue is injected into the exhaust stream before it enters the SCR catalyst. The amount injectedis carefully controlled based on the engine load and exhaust temperature.

The heat in the exhaust converts the Adblue into ammonia (NH₃) and carbon dioxide (CO₂).

The ammonia then reacts with nitrogen oxides (Nox) in the SCR catalyst, breaking them down into harless nitrogen (N₂) and water vapour (H₂O).

Post-treatment

The cleaned exhaust gases, now free of most of the harmful Nox emissions, are expelled through the tailpipe, significantly reducing the vehicle’s environmental impact.

What goes wrong?

Crystallization: AdBlue can crystallize if it’s not used frequently, causing blockages in the injector or pipes
Sensor Failures: The system relies on various sensors to monitor AdBlue levels and performance. These sensors can fail, causing inaccurate readings or false warnings.
Injector Issues: The AdBlue injector can clog or malfunction, leading to improper dosing and potentially increased emissions or system failures.
Temperature Sensitivity: AdBlue freezes at temperatures below -11°C (12°F). While systems are designed with heaters, malfunctions can occur, causing the fluid to freeze and not be pumped properly.
AdBlue Quality: Using low-quality AdBlue or fluid that’s contaminated can cause the system to malfunction, as impurities can block the injector or harm the catalyst.
System Warning: The dashboard often displays warnings about AdBlue levels or malfunctions, which may limit the vehicle’s performance if the problem is not addressed promptly.

How to prevent crystalisation and blockages

Wynn’s Crystal Clean and Protect dissolves crystals that have formed in the exhaust fluid tank, affecting the function of the level sensor and fluid pump.

Use Wynn’s Crystal Clean and Protect on every service and when topping up the vehicles Diesel Exhaust Fluid (AdBlue) to prevent the build-up of crystals forming in the Selective Catalytic Reduction (SCR) system.

Crystal Clean and Protect keeps the complete SCR system free from crystals. Preventing them from forming on the following components and ensure they function correctly: