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Diesel Oxidation Catalyst

The Donaldson Diesel Oxidation Catalyst (DOC) and DOC Muffler is a cost-effective, reliable emissions retrofit solution for reducing diesel emissions, with no maintenance. 


  • Broad engine coverage
  • Four-stroke diesel engines for on-road applications with engine horsepower ranges of 150-550 HP
  • Take-apart style DOC muffler is ideal for older vehicles (1988-1990) that generate greater levels of particulate matter


  • Corrosion resistant aluminized 409 grade stainless steel for surfaces exposed to the environment
  • Adds minimal backpressure to the exhaust system


  • DOC mufflers are designed to be a direct replacement for most original equipment mufflers
  • DOCs are designed to be installed in-line into the existing exhaust system, between the muffler and turbo charger
  • No maintenance required
  • Verified for U.S. EPA Voluntary Retrofit Program