Diesel Exhaust Fluid (DEF)

Even though the U.S. Environmental Protection Agency introduced new emissions standards in 2010 that require medium- and heavy-duty vehicles to significantly reduce engine emissions, many people still have questions about Diesel Exhaust Fluid (DEF), a fluid that removes harmful emissions from diesel engines. At Bear Oil Company, we have the answers!

DEF is a non-hazardous solution added to a special DEF tank on most new diesel vehicles. It looks like water and has a slight ammonia scent. DEF is never added directly to diesel fuel. It is sprayed into the exhaust and breaks down harmful gases associated with health issues such as respiratory and cardiac diseases. Vehicles equipped with DEF tanks will eventually stop running when the DEF tank is empty, until it is refilled.

If you have questions about DEF, including handling and storage, please contact us today. Our team can help you understand this relatively new technology

Can I Use Different Brands of DEF in My Tank?

Run the tank as empty as possible. DEF fluid from different certified suppliers can be mixed. 

What Happens if I Run Out of DEF?

When DEF gets low, there should be some alarm system alerting you. If it gets too low, the vehicle will go into a low power mode and will not start.

Is DEF Corrosive?

Of all the fluids in your car, DEF is the least hazardous. However, DEF is corrosive for some metals. Do not store DEF in metal containers made of the following materials: aluminum, carbon steel, copper, and zinc.

Do I Need to Wear Protective Clothing When Filling Up the DEF tank?

No special clothing is needed when filling up your vehicle with DEF. However, it can stain clothes and should be rinsed off with water if spilled on.

What Should I Do if There is a DEF Spill?

If you spill a small amount of DEF it can be washed away with water or wiped up. If left to dry it will turn into white crystals – these too can be washed away with water.

What is the Shelf Life of DEF?

DEF has a shelf life of two years. However this can be reduced if stored in direct sunlight or remains above 86 degrees for long periods.