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Diesel Exhaust Fluid (DEF)

The API Diesel Exhaust Fluid Certification Program is a voluntary program designed to certify and monitor the quality characteristics of diesel exhaust fluid intended to operate converters with selective catalytic reduction (SCR) in motor vehicles with diesel engines. Diesel exhaust fluid marketers that meet specific performance requirements for diesel exhaust fluid may be licensed to display the API Diesel Exhaust Fluid Certification Mark. 

Click here to access the current directory of licensees.

API Diesel Exhaust Fluid Certification has many benefits:  

  • Identifies for consumers diesel exhaust fluids that meet diesel engine manufacturer requirements.
  • Helps consumers find those fluids.
  • Gives consumers a choice of quality brands from which to choose.
  • Helps reduce Nitrogen Oxide emissions.
  • Provides rigorous monitoring of fluids in the marketplace.
  • Tests licensed fluids to ensure that they meet program requirements.
For more information please visit: www.apidef.org.