When your International or Navistar truck uses the Cummins ISB 6.7L engine, your emissions aftertreatment system is only as strong as its sensing and control points—especially the DEF head. The Navistar/International Cummins ISB 6.7L DEF Head Unit, built to OEM 3600821 specifications, is a critical module that ensures your SCR (Selective Catalytic Reduction) system performs as intended. A failing DEF head opens the door to warning codes, system derates, or compliance issues.
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Monitors DEF fluid level, temperature, and concentration, delivering accurate data to the engine control module
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Controls precise dosing of urea into the exhaust stream so NOx emissions are reduced properly
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Designed to match OEM 3600821 tolerances for plug-and-play compatibility with Navistar / International systems
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Helps prevent fault codes, emissions warnings, and engine derates that stem from sensor misreads or failures
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Constructed to withstand vibration, temperature extremes, and exposure to DEF’s chemical nature
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Simplified installation keeps downtime minimal when replacement is necessary
Don’t let a neglected DEF head become your emissions weak spot. Installing the OEM 3600821 Navistar/International Cummins ISB 6.7L DEF Head Unit restores system integrity, ensures accurate feedback, and helps your vehicle stay compliant in all conditions. In the ongoing race to meet environmental standards, this is one component you can’t afford to overlook.