Keeping SCR systems healthy – why AdBlue® handling and testing matter
CORRECT AdBlue® management is now a fleet-maintenance priority as South Africa’s transport sector adapts to tighter emissions expectations and the wider use of Selective Catalytic Reduction (SCR) systems.
AdBlue®, or Diesel Exhaust Fluid (DEF), is not a fuel additive. It is stored in a dedicated tank and injected into the exhaust stream ahead of the SCR catalyst, where heat converts it into ammonia, which reacts with nitrogen oxides (NOx) to produce harmless nitrogen and water vapour.
Condition monitoring specialist company, WearCheck, warns that AdBlue®’s performance hinges on quality. ISO 22241-compliant Adblue® offers reduced engine risk and compliant emissions performance in a healthy system. WearCheck Water laboratory manager, Michelle Wium, explains that the fluid is a precise 32.5% high-purity solution, where synthetically manufactured urea is mixed with demineralised water. She says even miniscule contamination can trigger expensive SCR problems.
WearCheck helps fleet operators, depots and OEM stakeholders manage contamination risks. WearCheck Water is the company’s water analysis division, and its laboratory, which is ISO 17025 accredited by SANAS to test AdBlue®/DEF, is the first laboratory in Africa with this specific accreditation. The test confirms whether AdBlue meets ISO 22241 requirements and provides objective, scientific evidence in quality disputes.
Wium notes a concerning rise in the rejection rate of fleets’ OEM warranty claims based on poor-quality Adblue®. “Regular testing is essential,” she says. “Contamination can occur even before the fluid reaches the vehicle, if wholesalers use unclean containers, allow dust and microbes to enter, or reuse equipment previously exposed to diesel, oil or grease. The consequences include crystallisation and deposits that clog injectors and lines, corrosion of components, SCR faults, limp-mode events and increased emissions exposure.”
WearCheck Water’s AdBlue® analysis focuses on compliance markers that indicate whether the solution is fit for purpose, including urea concentration and other chemical indicators that reveal contamination or degradation. Correct sampling is equally important. Wium recommends a clean container, typically HDPE/ stainless steel, which is sealed properly and labelled. “First flush the sampling point, discarding the initial volume to remove residue. Store the sample cool and dry until delivered for testing.
“Great results begin with storage discipline,” says Wium. “AdBlue® should be stored between 0°C and 30°C, out of direct sunlight, in sealed containers to prevent moisture ingress and airborne contamination. Shelf life shortens at higher temperatures, so cool storage is critical. Dispensing systems, dedicated to AdBlue®, must be clean and protected from dirt and oil. Suspect contamination? The safest decision is to test or replace the fluid immediately, rather than risk SCR-system damage.”
Fleet operators are urged to treat AdBlue® like a critical operating fluid, not a commodity. Combine reputable supply, correct storage and periodic verification testing, to avoid maintenance headaches with SCR systems.
Visit www.wearcheck.co.za, email marketing@wearcheck.co.za, or call WearCheck on +27 31 700 5460.
