
Cummins B6.7, L9 DOC Filter 2018-2024: OEM 4394820
CUMMINS B6.7, L9 DOC FILTER 2018-2024: OEM 4394820

ORDERS PLACED BEFORE 3PM EST WILL SHIP SAME DAY

WARRANTY
1M MILES OR 1 YEAR
PRODUCT DESCRIPTION
This is a Remanufactured Tamerx DOC Filter, Tamerx part number 102-0096RM-DOC-7 ( OEM Part Number 4394820 ). All parts are proudly remanufactured in the U.S.A. to the highest of OEM standards, and improvements are often applied to the original design in the remanufacturing process. This part is primarily made for a Cummins B6.7, L9, production years 2018-2024, and comes with a One Million Miles or One Year Warranty. For additional warranty info Click Here
Additional Notes: Inlet Catalyst
OEM NUMBERS
| Primary OEM | 4394820 |
| Additional OEM | 4394820 |
ADDITIONAL DETAILS
| CONDITION | Remanufactured |
| UPC / Barcode | 00840490549494 |
| WEIGHT | 35.00 LBS |
SHIPPING OPTIONS
Ship Weight : 35.00 LBS
UPS Ground, 2nd Day Air, Next Day Air
SHIPPING POLICY
Tamerx Diesel Products ships via UPS Ground. Next day air shipping can be arranged for a reasonable price of anywhere from $50.00 - $100.00 depending on the weight of the product and your location. We will do everything we can to make sure that you get the service you need. We understand how important it is to receive your order as quickly as possible.
In most cases Tamerx Diesel Products only needs one address, as long as your product is shipping to the same location as your billing information. In order to eliminate credit card fraud, your billing information must match the credit card you provide.
The terms, conditions, and details of our warranty vary from product to product. Specific warranty details can be found below.
Tamerx Diesel Products provides a replacement warranty on all of our parts. The duration and mileage limitations of the warranty vary by product and are specified on the product's detail page/item listing.
Please note that the warranty covers replacement of the part and the cost of shipping the replacement part to you only. It does not cover any shop, labor, towing, or any similar or related costs. This is not a "money back guarantee".
If you experience a problem with your part or it is not functioning properly, the correct warranty procedure is to call us at (510) 257-1777 (8:00 AM - 5:00 PM ET Monday through Friday). Be sure to have your order number and/or other relevant order information ready so we can easily locate your order and resolve your issue as quickly as possible. From that point, we will review with you any troubleshooting steps that may need to be taken and other areas or systems that can be checked to rule out external problems contributing to your part's issue. If a replacement is determined to be necessary, we will then arrange for your replacement part to ship out ASAP and issue any necessary return shipping labels and/or documents.
As is the case for the majority of the diesel products sold on Tamerx Diesel Products, your part's warranty is active as soon as you install it. In some other cases, warranty activation is contingent upon you sending us your core (i.e., your old part). Tamerx Diesel Products will provide you a return shipping label for parts that have a warranty with a core return condition. When we have received your core return, the part's warranty coverage begins. We reserve the right to void the product warranty if your core is not received within the allotted time, or if it isn't received at all. If the warranty for the diesel part you are purchasing has a core return requirement, it will be clearly noted on the product detail page/item listing.
What is a Core Charge?
A core charge (also called "core deposit") is similar to the deposit you might pay for a can or bottle of soda and is a standard requirement in the auto parts industry. For example, in many states, to promote recycling, you pay a deposit when you purchase a can of soda and receive your deposit back when you return the empty can. Many automotive parts have a core charge, or core price, that works in essentially the same way as a soda can deposit.
30 Day Core Charge Hold
You authorize Tamerx Diesel Products, to hold your credit card for the specified core charge amount and that you agree to return your core with 30 days of receiving the purchased part. When we have received your core return, the hold is released and the core charge payment is canceled.
The customer, or parts buyer, is responsible for any shipping costs associated with core returns unless otherwise specified in the product listing/detail page. Tamerx Diesel Products offers prepaid UPS shipping labels (SKU numbers UPS-CR1 and UPS-CR2) for use in returning your core that are available for purchase on our website during your shopping/order process.
The shipping label you will need to use for the core return is dependent upon what part you are purchasing. UPS-CR1 is good for cores weighing up to 20 pounds. UPS-CR2 is appropriate for shipping cores weighing 21 pounds or more. You must include enough information with the core return that clearly identifies it as a.) a Core Return, and b.) contains enough information we can use to clearly associate the core return with your order. Including a copy of the invoice or packing slip that came with the original shipment, clearly marked "Core Return", is ideal. Alternately, you can include a note marked as "Core Return" that includes your order number, full name and address, and phone number or other contact information. Failure to include this information with your returned core will most likely delay any due core credit being issued and/or delay any applicable warranty activation. Core returns need to be for the exact part purchased and cannot be damaged. Substituting another part in place of the part you have purchased is not acceptable.
All fluids must be drained.
If you have purchased a set or a parts package, you will need to return cores for all components of the set. For example, if you have purchaed a high pressure oil pump with an IPR valve, you will need to return both HPOP and IPR valve cores to receive proper credit. If you have purchased an EGR cooler/EGR valve package, your core return must consist of an EGR cooler core and an EGR valve core, or core credit will not be given.
Core Charges are often mandated by state legislature, and, as such, the actual core charge and taxes on the charge may vary depending on the state in which you buy your part. The Tamerx Diesel Products core charge presented to you online today with your item is representative of the most common core charge.
Engineered to support your emissions aftertreatment system, the Cummins B6.7 and L9 DOC Filter 2018–2024, OEM Part Number 4394820, is designed for select B6.7 and L9 engine applications. This diesel oxidation catalyst (DOC) converts harmful exhaust gases into less harmful emissions before they continue through the rest of the emissions system. Built to meet OEM specifications, it provides precise fitment and durable construction for demanding commercial and vocational use. A restricted or failing DOC filter can lead to warning lights, increased exhaust backpressure, or other aftertreatment concerns, making timely replacement important. Tamerx Diesel Products LLC offers dependable diesel components to help keep your Cummins engines operating cleanly and reliably.
FITMENT CHART
| YEAR | MAKE | ENGINE(S) | ||||
|---|---|---|---|---|---|---|
| 2018 | Cummins | B6.7 | L9 | |||
| 2019 | Cummins | B6.7 | L9 | |||
| 2020 | Cummins | B6.7 | L9 | |||
| 2021 | Cummins | B6.7 | L9 | |||
| 2022 | Cummins | B6.7 | L9 | |||
| 2023 | Cummins | B6.7 | L9 | |||
| 2024 | Cummins | B6.7 | L9 | |||
PEOPLE ALSO ASKS | BLOG(S)
What Are the Components of the Cummins B6.7, L9 DOC Filter 2018–2024: OEM 4394820?
The Cummins B6.7, L9 DOC (Diesel Oxidation Catalyst) Filter OEM 4394820 is a key emissions aftertreatment component used on 2018–2024 Cummins B6.7 and L9 engines. Although it is supplied as a single assembly, the DOC contains several internal and external parts that work together to chemically treat exhaust gases before they proceed to downstream systems like the Diesel Particulate Filter (DPF) and Selective Catalytic Reduction (SCR).
Primary DOC Components
- DOC Housing
- A durable steel or stainless-steel outer shell that protects internal elements and provides mounting points in the exhaust system.
- Catalyst Substrate
- A honeycomb-style core — typically ceramic or metal — with thousands of tiny channels that maximize surface area for chemical reactions.
- Catalyst Coating
- A layer of catalyst materials (often precious metals) applied to the substrate surfaces. These materials promote oxidation reactions that reduce specific exhaust gases.
- Inlet and Outlet Cones
- Internal guide sections that smooth the flow of exhaust gases into and out of the catalyst substrate.
Supporting & Sealing Elements
- Gaskets and Seals
- High-temperature seals that prevent exhaust leaks between the DOC and adjacent exhaust components.
- Mounting Flanges
- Machined surfaces and attachment points for secure connection to the engine’s exhaust pipe and downstream aftertreatment parts.
Sensor & Monitoring Interfaces
While the DOC itself does not contain active sensors, the assembly typically provides:
- Temperature Sensor Ports
- Locations where exhaust temperature sensors may be installed upstream or downstream for monitoring by the engine control module (ECM).
- Pressure Sensor Ports (in some systems)
- Interfaces for differential pressure sensors that help detect system restrictions.
How These Components Work Together
Exhaust gases leaving the engine enter the DOC housing and flow through the honeycomb catalyst substrate. The catalyst coating facilitates oxidation reactions that convert:
- Carbon monoxide (CO) into carbon dioxide (CO₂)
- Unburned hydrocarbons (HC) into water vapor (H₂O) and CO₂
These reactions also generate heat, helping raise exhaust temperature to levels needed for downstream aftertreatment processes like DPF regeneration.
The housing, flanges, and gaskets ensure a sealed, secure connection within the exhaust system, while sensor ports enable monitoring and control by the ECM.
Together, these components allow the Cummins B6.7, L9 DOC Filter OEM 4394820 to reduce harmful emissions and support efficient aftertreatment system operation.
The DOC (Diesel Oxidation Catalyst) filter reduces harmful exhaust gases by triggering a chemical reaction inside a coated catalyst substrate. Because it depends on clean exhaust flow and stable temperatures, contamination is the most common reason it fails.
The main cause of DOC filter failure is internal contamination from oil or coolant.
When engine oil or coolant enters the exhaust stream, it can coat the catalyst surface. This coating blocks the chemical reaction needed to convert emissions efficiently and often leads to catalyst efficiency fault codes.
Other contributing factors include:
- Excessive soot from incomplete combustion
- Faulty fuel injectors
- EGR system malfunctions
- Prolonged engine misfires
- Repeated overheating events
- Ignoring early warning lights
Overheating can also damage the internal substrate. If exhaust temperatures remain too high for extended periods, the catalyst structure may crack or melt, leading to restricted exhaust flow.
Engine issues that increase soot or unburned fuel can accelerate DOC wear and reduce overall efficiency.
Routine engine maintenance, repairing oil or coolant leaks quickly, and responding to warning lights promptly can significantly reduce the risk of premature DOC filter failure and help maintain proper emissions system function.
Yes — a clogged or failing DOC Filter can cause emissions-related diagnostic codes and impact aftertreatment performance.
Yes — it is designed to integrate with the engine’s original emissions sensors and control systems.
The DOC Filter begins the oxidation of pollutants before gases reach later aftertreatment stages, helping meet emissions standards.
Yes — aftermarket and remanufactured versions are available that meet OEM-grade specifications.






