MCNEILUS Cummins DEF Head Unit

Reliable SCR Fluid Control for McNeilus: OEM DEF Head Unit (1604691)

What is it?
The OEM 1604691 DEF Head Unit is a factory-engineered assembly designed for McNeilus trucks with Cummins engines. It serves as the DEF (Diesel Exhaust Fluid) tank header—housing sensors for fluid level (and often temperature or quality) detecting—ensuring your emissions system works with precise fluid management.

Why choose this OEM DEF Head Unit?
This unit is manufactured to McNeilus / Cummins original standards, ensuring correct sensor calibration, proper sealing, and direct fitment. Choosing the genuine part avoids common issues such as false DEF level warnings, leakage, or SCR system malfunctions that occur with aftermarket substitutes.

Key Benefits
 ✅ Direct OEM fit for McNeilus Cummins vehicles
 ✅ Accurate sensor monitoring for DEF fluid level and/or quality
 ✅ Proper sealing to prevent leaks and maintain system integrity
 ✅ Integrates with OEM wiring and diagnostics to avoid error codes
 ✅ Built for rugged, long‑term service in real‑world conditions

Applications
Ideal for McNeilus refuse and collection vehicles powered by Cummins engines using DEF systems. Regularly used in municipal and fleet applications, where reliable exhaust aftertreatment is essential for compliance and continuous operation.

Installation Notes
Install with engine turned off and DEF system depressurized. Clean the area around the DEF tank opening, remove old assembly, and fit the new unit using OEM torque specifications. Replace any required gaskets or O‑rings. After installation, verify DEF system status using diagnostics and ensure correct fluid readings.

Final Thoughts
If your McNeilus Cummins unit is showing DEF warnings, fluid reading issues, or SCR derate messages, the OEM 1604691 DEF Head Unit is the reliable fix. Restores factory‑matched functionality, reduces downtime, and ensures emissions compliance.