More commonly known as AdBlue, DEF is an additive that mixes with exhaust emissions to neutralize NOx. It is a urea and water ...

For most diesel-powered engines, DEF is vital so the vehicle performs at its best. Here's what it is exactly and what the acronym stands for.

Generally, DEF has an average shelf life of 12 months. Estimates, however, can vary based on several factors. For instance, if you store DEF in direct sunlight or high heat, its shelf life will ...