Myths about Diesel Exhaust Fluid


Diesel exhaust fluid, also known as DEF, is a solution that is sprayed onto the exhaust stream of diesel vehicles to break down nitrogen oxides into much safer nitrogen and water. DEF is meant to improve air quality by reducing the pollutants in the air.


Here are a few myths about diesel exhaust fluid that you may not have heard before:

Only a Service Technician Can Refill Your DEF Fluid

This assumption is completely false. When making your purchase, the dealer may insist that this is true and that only a certified technician can refill the fluid for you, but that’s just an attempt to squeeze an extra dollar from you. Most automobiles have their fuel filler next to the diesel exhaust fluid, but a few are under the hood or in the trunk. The element that remains the same is, if you know where the DEF fluid needs to go, all it takes is pouring it in. You can do that yourself.

You Can Only Buy DEF Fluid at a Dealer

Salespeople often tell you this line as well, but it’s another false statement. They hype up the need to buy more fluid than you need to from them in order to stock up, but it’s just as accessible as any other automotive fluid at your location auto parts and equipment store. You can also find it online! It doesn’t take going through a dealer to get DEF fluid.

Avoiding a Dealer Voids Your Warranty

If someone sells you this line, don’t buy it. It’s illegal for a dealership to require you to purchase any oils, lubricants, or even DEF fluid strictly from them with the threat of voiding an associated warranty through them. So, not only do you not have to listen, but such a threat can give you grounds for legal action.

Non-Factory Fluid Hurts Overall Performance

This myth is just a way to steer consumers towards buying more expensive DEF fluid that isn’t essential. Don’t let these claims cause you to waste another dollar. Choose the fluids that are effective, affordable, and right for your vehicle, regardless of if the DEF manufacturers labeled their fluid factory or non-factory. The reviews for the type of fluid for your vehicle, and your own personal experience with your vehicle, won’t steer you wrong.