Mack DOC : OEM 21850643

Emissions Reliability for Mack MP-Series Engines

What Is It?

The Diesel Oxidation Catalyst (DOC) OEM 21850643 is a direct-fit emissions component designed for Mack diesel engines. It functions as the first line of defense in the aftertreatment system, oxidizing hydrocarbons (HC) and carbon monoxide (CO) from the exhaust to prepare it for downstream treatment in the Diesel Particulate Filter (DPF).

Why Choose OEM 21850643?

Built to Mack’s OEM specifications, the 21850643 DOC ensures correct fitment and dependable emissions control. It’s engineered to work under high heat conditions, supporting effective DPF operation and maintaining system efficiency.

Key Benefits

✅ Designed for Mack Diesel Platforms: Tailored fit for MP-series engines
✅ Reduces CO and HC Emissions: Converts harmful gases into less toxic compounds
✅ Optimizes DPF Function: Helps maintain proper exhaust temperature and flow
✅ Thermal Endurance: Withstands repeated high-temperature regeneration events
✅ OEM Sensor Compatibility: Accepts factory-installed temperature and pressure sensors

Applications

This DOC is used in various Mack trucks equipped with MP7, MP8, or MP10 engines that utilize OEM-configured aftertreatment systems. It is ideal for fleets operating in long-haul, construction, or municipal settings where emissions compliance and durability are required.

Installation Notes

Installation should be completed by a certified technician. Ensure clamps, gaskets, and sensors are inspected and replaced if necessary. After installation, reset emissions parameters in the engine control module using Mack-compatible diagnostic tools. A manual regeneration may be needed to bring the system back online.

Final Thoughts

The OEM 21850643 DOC offers reliable emissions treatment for Mack diesel vehicles. Its factory-matched design, heat-resistant build, and seamless integration with the emissions system make it a solid choice for maintaining compliance and reducing service interruptions.