Cummins QSB4.5, 3.8 SCR Filter 2018-2024: OEM 5505819

Engine-Matched SCR Exhaust Filter for Cummins QSB4.5 & 3.8 Engines

What is it?
The Cummins QSB4.5, 3.8 SCR Filter, with OEM part number 5505819, is a key emissions aftertreatment component designed for Cummins QSB4.5 and 3.8-liter diesel engines. Installed as part of the Selective Catalytic Reduction (SCR) system, this filter helps condition exhaust gases so that nitrogen oxides (NOx) can be more effectively reduced when interacting with Diesel Exhaust Fluid (DEF) downstream.

Why choose this SCR Filter?
This SCR filter is built to Cummins’ original specifications for the QSB4.5 and 3.8 platforms, ensuring precise fitment and reliable integration with DEF dosing components, emissions sensors, and the SCR catalyst. Over time, soot and exhaust deposits can accumulate in the filter and hinder how gases are conditioned prior to NOx conversion. Using the correct OEM-specified filter helps maintain balanced exhaust flow and supports coordinated emissions system operation.

Key Benefits
✅ Designed specifically for Cummins QSB4.5 and 3.8 aftertreatment systems
✅ Helps prepare exhaust gases for effective NOx reduction
✅ Supports stable interaction with DEF dosing and emissions sensors
✅ Direct-fit replacement — no modifications required
✅ Built to tolerate heavy-duty exhaust conditions

Applications
This SCR filter is suitable for medium- and heavy-duty trucks and commercial vehicles equipped with Cummins QSB4.5 or 3.8 diesel engines. Typical applications include delivery rigs, vocational trucks, regional transport units, work equipment, and other commercial platforms where emissions control and regulated exhaust handling are essential.

Installation Notes
Before servicing, allow the exhaust and aftertreatment system to fully cool. Remove the existing SCR filter and inspect nearby DEF lines, sensors, and mounting hardware for signs of soot buildup or wear. Install the replacement filter using proper seals and clamps to ensure a secure, leak-free fit. After installation, clear any stored system codes and verify correct emissions system behavior with appropriate diagnostics.

Final Thoughts
If your Cummins-powered vehicle is showing emissions warnings, uneven NOx behavior, or irregular aftertreatment responses, replacing the SCR filter with the correct OEM-specified unit can help restore balanced exhaust conditioning and steadier system performance. The Cummins QSB4.5, 3.8 SCR Filter (OEM 5505819) plays an important role in managing regulated exhaust chemistry and supporting dependable engine operation.