Everything You Need to Know About Diesel Exhaust Fluid (DEF)

Diesel Exhaust Fluid (DEF) is a crucial component for companies using heavy-duty diesel engines to keep their vehicles and machinery within federal emission guidelines. But how does DEF work, and how can you prevent it from going bad? In this article, we'll answer these questions and more.

Diesel Exhaust Fluid

What is DEF, and How Does it Work?

DEF is a mixture of deionized water and urea that is added to the exhaust system of diesel vehicles and machinery. When DEF is sprayed into the exhaust stream, it reacts with the harmful nitrogen oxide (NOx) emissions, converting them into water and nitrogen gas, which are much less harmful to the environment.

Can DEF Go Bad?

DEF only goes bad if it's contaminated by another material, such as diesel fuel, antifreeze, windshield washer fluid, dirt, or water. If this happens, the contaminated DEF should be disposed of following the instructions in the Safety Data Sheets (SDS) and local regulations. However, DEF does not go bad with age. While its shelf life is estimated to be 12-18 months, it can last longer if stored properly.

How Long Does DEF Last in Storage?

DEF does not go bad with age, but it has a recommended shelf life of 12-18 months. The cooler it's kept, the longer its shelf life. If you have DEF that hasn't been contaminated but is beyond its recommended shelf life, you can test it with a refractometer to see if the urea content is still within the acceptable range. However, most users would dispose of older DEF due to age concerns, whether real or perceived.

How Do You Know DEF is Bad?

The easiest way to spot bad DEF is by its appearance. DEF is naturally clear, so if it looks cloudy or discolored in any way, it's probably old or contaminated. Other signs of bad DEF include increased consumption by equipment, decreased effectiveness, equipment issues or failure, component damage, and Selective Catalytic Reduction (SCR) system issues.

Storing DEF in the Summer

When storing DEF, it's important to keep it in a cool, dry place with a temperature between 12 to 86 degrees Fahrenheit. DEF should never be exposed to sunlight, as this can cause it to release more ammonia, making it unpleasant to work with. Additionally, DEF should never be dispensed in a small, confined area, no matter its age or quality. Instead, it should be dispensed in a well-ventilated area or outdoor environment.

Can DEF freeze in cold temperatures?

Yes, DEF can freeze in cold temperatures. However, it doesn't become unusable when it freezes. When DEF freezes, the urea and water separate, causing the solution to thicken. Once the solution thaws, it returns to its original consistency without any adverse effects. It's important to note that if DEF is frozen, it should not be mixed or agitated until it thaws completely.

How often should DEF be refilled?

The frequency of DEF refills depends on several factors, such as the size of the DEF tank, the equipment's usage, and the operating conditions. Generally, heavy-duty trucks and machinery use about 2-3% of DEF for every gallon of diesel fuel. This means that if a truck uses 10 gallons of diesel fuel, it will need about 0.2-0.3 gallons of DEF. It's important to monitor the DEF tank's level regularly and refill it as needed to avoid running out of DEF, which can lead to equipment failure or violation of emission regulations.

Can DEF be mixed with other fluids, such as diesel or oil?

No, DEF should never be mixed with other fluids, such as diesel or oil. Doing so will contaminate the DEF and render it ineffective. If DEF is contaminated, it should be disposed of properly, following the instructions in the SDS sheets and local regulations.

Is DEF harmful to humans or the environment?

No, DEF is not harmful to humans or the environment. DEF is a non-toxic, non-flammable, and biodegradable solution. It's made of deionized water and urea, which are both safe for humans and the environment. However, like with any chemical, it's important to handle DEF with care and follow the recommended safety procedures to avoid any accidents or spills.

DEF Delivery Services by Rhino Fuel

Rhino offers wholesale DEF delivery in various sizes, including 2.5-gallon jugs, 55-gallon drums, 350 gallon totes, and mini bulk/bulk containers. Their delivery service is convenient and reliable, ensuring that your vehicles and equipment always have a sufficient supply of DEF to maintain their emission standards. Contact Rhino Fuel to learn more about their DEF delivery options.