Boost Engine Integrity with Cummins B6.7 & L9 DOC
What is it?
The Diesel Oxidation Catalyst (DOC) for the Cummins B6.7 and L9 engines is a vital emissions-control component. Located early in the exhaust system, it converts hydrocarbons (HC) and carbon monoxide (CO) into less harmful gases, preparing exhaust flow for downstream treatment and supporting overall system efficiency.
Why choose this DOC?
Specifically designed for the Cummins B6.7 and L9 engine models, this DOC ensures precise fitment and reliable emissions performance. A damaged or clogged catalyst can cause increased back-pressure, frequent regenerations, or fault codes—installing the right replacement helps avoid these issues and keeps the system operating correctly.
Key Benefits
✅ Converts HC and CO into safer exhaust output
✅ Protects downstream DPF, SCR, and other after-treatment components
✅ Helps reduce exhaust restriction and back-pressure
✅ Direct-fit design—no modifications required
✅ Built for heavy-duty use, high temperatures and long duty cycles
Applications
Ideal for trucks, buses and equipment equipped with Cummins B6.7 or L9 engines, especially in commercial or vocational use where emissions control, system reliability and serviceability matter.
Installation Notes
Ensure the exhaust system is cool before servicing. Inspect the catalyst housing and surrounding connections for damage or soot buildup. Replace all seals, gaskets and clamps with each installation. After fitting the new DOC, clear any fault codes and monitor exhaust system behavior to confirm correct operation.
Final Thoughts
If your B6.7 or L9 engine is experiencing emissions faults, elevated back-pressure, or inefficient after-treatment performance, installing the correct DOC is a smart decision. With proper fit and construction, this part helps restore clean exhaust flow and supports long-term system reliability.