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Diesel Exhaust Fluid

When it comes to DEF, quality and proper handling is essential in choosing a supplier.

Santex has the expertise to cover all your DEF needs. From 2.5 gallon jugs, Drum, Totes or bulk deliveries.

DEF Frequently ask questions.

Everyone who owns or operates heavy equipment has likely heard of Diesel Exhaust Fluid, or DEF. Yet not everyone is fully aware of what exactly it is, what it does, and how it fits into an existing operation. Fortunately, for every question about DEF, there’s an answer.

1. What Is DEF?

Diesel exhaust fluid, commonly referred to as DEF, is a solution of 67.5% deionized water and 32.5% high-purity urea, that’s used to chemically reduce nitrogen oxides emissions (NOx) from non-road mobile machinery and heavy equipment.
Just as important as knowing what DEF is – knowing what it’s not:

  • DEF is not a fuel additive.
  • DEF is not toxic or harmful to humans or animals.
  • DEF is not flammable or explosive.

While safe, DEF should still be handled with care to avoid unnecessary spills, contact with eyes, or accidental ingestion.

In the event of a spill on the floor, cover and contain the spill with an absorbent, non-combustible material such as sand. Shovel and dispose of the material in an appropriate container. If DEF is spilled in a sink, on a vehicle, on clothes or gets into the eyes, flush immediately and thoroughly with water.

2. How Does DEF Work?

DEF is used in Final Tier4 diesel engines with Selective Catalytic Reduction (SCR) systems. SCR is an after-treatment technology that treats exhaust gas downstream of the engine, with the goal of reducing levels of NOx emissions that are harmful to the environment and health. DEF is injected into the exhaust stream, prior to the SCR catalyst, and converts NOx into harmless nitrogen and water.

3. Why Does My Equipment Need DEF?

All Final Tier4 engines are equipped with SCR systems. Not only does this technology work with DEF to reduce NOx, the SCR process allows engines to operate at maximum efficiency for better fuel economy and lower costs.

4. How Do I Use DEF?

Although its name may imply otherwise, DEF should never be used in the diesel fuel tank. It should only be used in the appropriate, dedicated DEF tank, which features a smaller opening than a fuel tank and a blue cap so it’s easy to identify.

5. How Much DEF Can I Expect My Equipment To Use?

Every engine varies in its use of DEF. John Deere engines are designed to use less DEF than similar engines; typical DEF use is 1-3% of fuel consumed. So for every 100 gallons of diesel fuel consumed by a John Deere tractor, approximately 2 gallons of DEF would be needed.