Diesel Exhaust Fluid: What Is It and Why Does It Matter?

Diesel Exhaust Fluid: What Is It and Why Does It Matter?

Revamping your old truck or just purchased a new one? You’re going to have to learn about diesel exhaust fluid for your vehicle, and why you need it if you want it to be in tip-top shape.

Any diesel-fueled vehicle built on or after 2010 is furnished with Selective Catalytic Reduction (SCR) and require the use of diesel exhaust fluid.

What Is Diesel Exhaust Fluid?

Diesel Exhaust Fluid, or DEF, is comprised of de-ionized water and urea, a non-hazardous solution. Your favorite diesel vehicle releases NOx emissions into the air, and DEF works to reduce emissions, and prevent harm. It does this by turning the emissions into innocuous water, oxygen, and nitrogen.

DEF is not stored in the diesel tanks, but has its own tank, meaning it never comes in contact with the actual diesel.

Diesel engines have been using this technology since 2010. Newer diesel vehicles require less fluid than big diesel engine trucks.

How Much DEF Do I Need?

Diesel vehicles consume anywhere from 2 to 10 percent of the fuel that’s used. DEF is often paired with a process called exhaust gas recirculation (EGR). EGR and DEF are negatively correlated - if an engine uses more EGR, the less DEF it needs.

The amount of DEF a vehicle needs is also slightly dependent on the climate in which they exist. If you live in a humid or cold area, your vehicle consumes less DEF, whereas a dry and hot environment uses more.

The good thing is that DEF is becoming a standard, and is readily available at most gas stations or truck stops, often directly in the pump. If you’re the owner of multiple diesel vehicles, you can purchase enough for your entire fleet.

If you happen to run out of DEF before refilling, the vehicle speed will slow down. It won’t return to normal until you’ve topped out your fluid. If your vehicle is post-2010, it has lights to alert you when your fluid is getting low, and they start flashing when you’re almost out.

The Cost of DEF

DEF ranges from two to three dollars a gallon. The diesel engine is the expensive part, however. Newer engines fitting Tier 4 requirements are almost twice the price of Tier 3 machines.

DEF’s lifespan is determined by the facility it’s stored in. If the facility is an optimal temperature of 12 degrees Fahrenheit and 86 degrees Fahrenheit, the life is under two years.

But, if it’s stored under 65 degrees, outside of direct sunlight, and in a dry environment, your DEF will last two years on the shelf.

This is the cost of sustainability. The better the engine and fewer emissions, the higher the price tag.

DEF for the Win

Refilling your diesel exhaust fluid is comparative to getting an oil change in a car. Let it go for too long, and it may have irreparable damage to your engine. Monitor your DEF closely, make sure you're always topped off and feel good about taking care of the environment while you're doing it.

If you're interested in showing off your love for diesel trucks in other ways, check out our store today!

1 comment

  • Donald

    Def is bad for the motor and it’s a heath hazzard it’s another way for the epa government’s way to poison us it urea you don’t heat urea up to 1200 degrees that’s a ticking time bomb waiting to go off the government is poisoning us with this

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