If your truck, bus or newer diesel car has a “DEF” tank next to the fuel tank, you already use it. Here is what it is, in plain words.
What AUS32 is
AUS32 (Aqueous Urea Solution 32.5%), also sold as Diesel Exhaust Fluid (DEF), is a clear liquid made of 32.5% high-purity urea and 67.5% demineralised water. It is not a fuel and it is not an additive for your diesel. It goes into its own separate tank.
What it does in the engine
Diesel engines produce nitrogen oxides (NOx), gases that harm air quality and health. Modern vehicles clean them with a system called SCR (Selective Catalytic Reduction):
- A small amount of AUS32 is sprayed into the hot exhaust stream.
- The heat turns the urea into ammonia.
- In the SCR catalyst, the ammonia reacts with NOx and turns it into harmless nitrogen and water vapour.
Consumption is typically around 3-5% of the diesel you burn, so a vehicle that uses 100 litres of diesel needs roughly 3-5 litres of AUS32.
Why quality matters
The international standard ISO 22241 defines the required concentration and the limits for impurities such as metals, phosphates and aldehydes. This matters because the fluid passes through an injector and a catalyst that are expensive to replace. Low-grade urea or a diluted product can leave deposits, clog the injector and damage the SCR system.
Rule of thumb: the cheapest fluid is not the cheapest option if it ends with a catalyst repair.
About BluVera AUS32
BluVera AUS32 is made with BASF raw material and supplied in 10-litre canisters for cars, vans and small operators, and 1000-litre IBC tanks for fleets, stations and wholesale. We deliver across Albania.
Which vehicles need it?
Most diesel trucks and buses built to Euro 4/5/6, and many diesel cars from Euro 6 on, use SCR. If you are not sure, look for a blue cap next to the fuel cap or a DEF gauge in the manual and dashboard.