Cummins B6.7, L9 DOC Filter 2018-2021: OEM 5418359

Engine-Matched Exhaust Treatment for Cummins B6.7 & L9 Engines (2018–2021)

What is it?
The Diesel Oxidation Catalyst (DOC) filter for Cummins B6.7 and L9 engines, covering model years 2018–2021 and referenced by OEM part number 5418359, is a core emissions-control component. Positioned early in the aftertreatment system, it helps convert hydrocarbons (HC) and carbon monoxide (CO) in the exhaust stream into less harmful compounds before the gases proceed through the remaining emissions components, supporting more stable system operation.

Why choose this DOC Filter?
Engineered to align with Cummins’ original design specifications for B6.7 and L9 engines, this DOC filter provides exact fitment and assures compatibility with the engine’s aftertreatment layout. When a DOC filter becomes restricted, clogged, or aged, it can impede normal exhaust flow and contribute to system warnings or erratic aftertreatment behavior. Choosing the correct OEM-specified DOC filter helps maintain balanced exhaust conditioning and supports consistent runs.

Key Benefits
✅ Tailored for Cummins B6.7 and L9 engine exhaust characteristics
✅ Helps condition exhaust gases for proper downstream treatment
✅ Promotes consistent exhaust flow behavior
✅ Direct-fit design — no modifications required
✅ Built to withstand high temperature and demanding use conditions

Applications
This DOC filter is suitable for medium- to heavy-duty trucks and commercial equipment powered by Cummins B6.7 and L9 engines manufactured between 2018 and 2021. Typical applications include delivery vehicles, vocational trucks, fleet units, and other machines where dependable emissions control and coordinated aftertreatment behavior are important.

Installation Notes
Before servicing, allow the exhaust and aftertreatment system to cool completely. Remove the existing DOC filter, inspecting surrounding exhaust pipes, sensor mounts, and hardware for soot buildup or damage. Install the replacement DOC filter using new gaskets, clamps, and seals to ensure proper sealing. After installation, clear any stored fault codes and verify correct exhaust behavior with diagnostic checks.

Final Thoughts
If your Cummins B6.7 or L9-equipped vehicle is experiencing signs of elevated exhaust restriction or aftertreatment alerts, installing the proper OEM-specified DOC filter can help restore coordinated exhaust conditioning. The Cummins B6.7, L9 DOC Filter (OEM 5418359) plays a foundational role in maintaining emissions-control system integrity and supporting dependable vehicle operation.