What is diesel exhaust fluid?


Quick Answer

Diesel exhaust fluid is a non-hazardous solution applied to the exhaust stream of diesel vehicles to break down nitrous oxide emissions into nitrogen and water. This system, called ���selective catalytic reduction,��� is found on 2010 and later model diesel vehicles.

Continue Reading
What is diesel exhaust fluid?
Credit: Helmut Seisenberger iStock / Getty Images Plus Getty Images

Full Answer

Diesel exhaust fluid is comprised of 32.5 percent urea and 67.5 percent de-ionized water. DEF is not a fuel additive and is stored in a separate container from diesel, and the two never come into contact. The fluid has a shelf life of up to two years, but will expire more quickly if it remains above 86 F for an extended period or is exposed to direct sunlight.

Learn more about Car Parts & Maintenance

Related Questions