Posted on 5/1/2025
If you own a modern diesel vehicle, you’ve probably heard of Diesel Exhaust Fluid (DEF). But what exactly is it, why is it so important, and what happens if you ignore it? In this deep dive, we’ll cover everything from its composition to why you should *never* resort to peeing in the tank (yes, some people do that!). Plus, we’ll touch on maintenance tips and what happens when things go wrong. What Is DEF Fluid? DEF is a non-toxic, urea-based solution used in Selective Catalytic Reduction (SCR) systems to reduce harmful nitrogen oxide (NOx) emissions from diesel engines. It’s a clear, odorless liquid made of: - 32.5% high-purity urea - 67.5% deionized water When injected into the exhaust stream, DEF breaks down NOx emissions into harmless nitrogen and water vapor, making your diesel vehicle much cleaner and more environmentally friendly. Is DEF Toxic or Harmful? While DEF is not flammable or dangerously toxic, it is mildly ... read more