Diesel Exhaust Fluid (DEF): Product Spotlight & Why Buy

Many fleets have a challenging relationship with DEF and the SCR system as a whole, but it doesn't have to be that way! The EPA regulations around emissions have been in place for 13 years, and engine manufacturers have been proactive in adapting developing new technology. Thompson Truck & Trailer, with 6 locations in Cedar Rapids, Davenport, Dubuque, Waterloo, and Sterling, is able to provide insight into DEF and exactly what you need to do to keep your truck in service and EPA compliant. 

What is it? 

DEF (Diesel Exhaust Fluid) was introduced in 2010 in response to the Environmental Protection Agency’s (EPA) tightening of emissions standards on diesel machines. This mandate required all medium and heavy duty diesel vehicles to significantly reduce engine emissions for all engines manufactured 2010 and newer. DEF is a part of the larger Selective Catalytic Reduction (SCR) system, which works to drastically reduce the amount of pollution emitted from vehicles. DEF is a clear, colorless, non-hazardous liquid looking exactly like water but that has a slight odor of ammonia. It is composed of urea and deionized water. The urea component is an organic compound made up of nitrogen, hydrogen, carbon and oxygen.

How does it work? 

DEF is not a fuel additive and has no influence on the tuning and efficiency of diesel engines. Instead, it is an additive used in a vehicle's aftertreatment system. There are many components at play, but in short, the way it works is that the fluid, an organic compound comprising urea and deionized water, is mixed with the hot gases that follow diesel combustion, breaking DEF down into ammonia and carbon dioxide. These two gases meet with the diesel exhaust and chemically bond with the nitrogen oxides, thus resulting in nitrogen and water exiting the tailpipe. The end result is a much cleaner diesel exhaust.

How much do I need? 

The EPA has minimum refill intervals for light heavy duty vehicles, but a good rule of thumb is to top off your DEF tank every time you fuel up your truck. DEF consumption is expected to be approximately 2 percent of fuel consumption, depending on vehicle application and geography, etc. The cost of running out of DEF can be days, weeks or even months of downtime if the truck is run too long without it. There is no sense in risking it. Instead, stock up on DEF from Thompson and ensure that your fleet is always covered.

How should I store it? 

DEF is a non-hazardous mixture of 32.5% high purity synthetic and 67.5% deionized water. DEF is considered non-toxic and non-flammable, but should still be handled with care in storage. If stored at 60 degrees, shelf life can be up to 36 months. The warmer it is, the shorter the shelf life becomes. If being stored in a bulk bin or container, the container must be brand new. A tank that has previously held any other product will contaminate the DEF. DEF can be corrosive to certain materials, so all personnel should handle with care. 

Okay, I’m ready to buy.

Thompson is your one-stop shop for all your heavy duty truck needs… Including DEF. Our parts department offers Fleetrite DEF, sold in 2.5 gallon jugs (Part #FLTFP). For your convenience, you can order online through RepairLink, or contact us!