Because of Selective Catalytic Reduction (SCR) technology which uses Diesel Exhaust Fluid (DEF), today’s trucks are able to meet the tightened EPA Emission levels while providing the power and fuel efficiency demanded by today’s Fleet Managers and Owner Operators.

Tilley Lubricant’s carrier DEF manufactured by Colonial Chemical Company.  Colonial Chemical manufacturers Diesel Exhaust fluid which meets the industry standard ISO 22241 spec and was the first producer of American Petroleum Institute (API) certified DEF in the United States.  As a leader in the production and distribution of DEF, Tilley Lubricants and Colonial DEF will provide you with reliability and piece of mind that your DEF will be free of impurity and work is intended.  Tilley Lubricants can supply bulk DEF to the Maryland, Virginia, Delaware, and Southern Pennsylvania market (1,000 gallon minimum per delivery) as well as 330 gallons totes, 55 gallon drums, 2.5 gallon jugs, and 4×1 gallon cases.


DEF Facts
  • What is DEF and how should I use it?

    DEF is a high purity solution of urea in de-ionized water (32.5%). It is used to chemically reduce NOx emissions from                 vehicles powered by diesel engines. DEF is contained in a separate tank and sprayed into the exhaust gases. Never fill the diesel fuel tank with DEF.

  • How much DEF will I need?

    Your DEF consumption will be approximately 2-3% of your diesel fuel consumption (approx 2-3 gallons for every 100                gallons of diesel used.)

  • Is DEF harmful?

    DEF is not harmful neither for humans or animals. DEF is not explosive and is non-toxic. If you get it on your skin or                  clothes, rinse with plenty of water.  DEF is not subject to any hazardous product regulations.

  • Will DEF burn?

    DEF does not burn and will not aid combustion.

  • DEF Storage

Solutions can be tailored to suit customer needs allowing for the usual precautions to prevent spillage into nearby drains.  DEF has a shelf life of 18 months if the stipulated storage conditions are observed. However, DEF that has been stored for longer than 18 months may still be perfectly usable and simply needs to be analyzed to check that it still conforms to the DEF specification. (Storage temperatures between 25°F – 80°F are recommended.)


Tips on How to Use DEF


  • Only fill DEF into the DEF tank. Look for the Blue Cap marked “DEF.”
  • Keep your DEF equipment clean and free from dust or dirt.
  • Use dedicated equipment for DEF.
  • You do not need to wear protective clothing while filling DEF.
  • If overheated, DEF containers can be chilled by standing in water.
  • DEF freezes at 12°F.
  • Only use DEF that has been delivered in dedicated, sealed packages designed for DEF.


  • Do NOT fill DEF into the Diesel Fuel tank!
  • Do NOT fill Diesel Fuel into the DEF tank!
  • Never add tap water to the DEF or DEF tank
  • Avoid getting DEF on your clothes and skin. But if you do, it can easily be removed by using water.
  • If spilled, wash with water, as the surface might get slippery.
  • Do not use DEF when mixed with water or other substances, especially diesel fuel.
  • Never use shop equipment (containers, funnels, etc) that have been used with other materials.