Cummins ISF3.8 DEF Doser Injector 2018-2024: OEM 4387109
CUMMINS ISF3.8 DEF DOSER INJECTOR 2018-2024: OEM 4387109
ORDERS PLACED BEFORE 3PM EST WILL SHIP SAME DAY
WARRANTY
1M MILES OR 1 YEAR
PRODUCT DESCRIPTION
This is a New, Tamerx DEF Doser Injector, Tamerx part number 4387109TX ( OEM Part Number 4387109 ).This part is primarily made for a Cummins ISF3.8, production years 2018-2024, and comes with a One Million Miles or One Year Warranty. For additional warranty info Click Here
OEM NUMBERS
| Primary OEM | 4387109 |
| Additional OEM | 4387109 |
ADDITIONAL DETAILS
| CONDITION | New |
| UPC / Barcode | 00840490542105 |
| WEIGHT | 2.00 LBS |
SHIPPING OPTIONS
Ship Weight : 2.00 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.
"This Product Doesn't Have a Core"
Proper DEF delivery is essential for maintaining emissions compliance, and the Cummins ISF3.8 DEF Doser Injector 2018–2024, OEM Part Number 4387109, is designed to do exactly that. Engineered specifically for Cummins ISF3.8 applications, this injector precisely meters Diesel Exhaust Fluid into the exhaust stream to support effective aftertreatment system operation. Built to meet OEM specifications, it provides accurate fitment and dependable functionality across 2018–2024 model years. A failing DEF doser injector can lead to fault codes, warning lights, or irregular DEF flow, making replacement an important step in restoring proper system operation. Tamerx Diesel Products LLC supplies reliable diesel components you can count on for consistent and efficient engine function.
FITMENT CHART
| YEAR | MAKE | ENGINE(S) | ||||
|---|---|---|---|---|---|---|
| 2018 | Cummins | ISF3.8 | ||||
| 2019 | Cummins | ISF3.8 | ||||
| 2020 | Cummins | ISF3.8 | ||||
| 2021 | Cummins | ISF3.8 | ||||
| 2022 | Cummins | ISF3.8 | ||||
| 2023 | Cummins | ISF3.8 | ||||
| 2024 | Cummins | ISF3.8 | ||||
PEOPLE ALSO ASKS | BLOG(S)
Proper maintenance of your Cummins ISF3.8 DEF Doser Injector OEM 4387109 is essential for keeping the SCR (Selective Catalytic Reduction) system operating efficiently. This injector is responsible for delivering precise amounts of Diesel Exhaust Fluid (DEF) into the exhaust stream to reduce NOx emissions.
Because DEF systems are sensitive to contamination and buildup, preventative care is critical to avoid clogging or dosing issues.
To properly maintain your Cummins ISF3.8 DEF doser injector:
- Use only DEF that meets ISO 22241 quality standards
- Store DEF in sealed containers away from direct sunlight and extreme temperatures
- Keep the DEF tank cap tightly closed to prevent contamination
- Inspect DEF lines and fittings for leaks or crystallization
- Address warning lights or fault codes promptly
- Follow recommended service intervals for the aftertreatment system
DEF crystallization is one of the most common issues affecting doser injectors. When DEF dries, it can leave behind deposits that restrict spray patterns. Periodic inspection of the injector tip and surrounding exhaust components can help identify early buildup.
It is also important to maintain related components such as DEF pumps, sensors, and wiring connections. These parts work together with the doser injector to regulate fluid delivery accurately.
By maintaining clean DEF, monitoring the system regularly, and responding quickly to diagnostic alerts, you can help extend the service life of your Cummins ISF3.8 DEF Doser Injector OEM 4387109 and maintain proper emissions system function.
The DEF doser injector sprays Diesel Exhaust Fluid into the exhaust stream to help reduce emissions. When it begins to fail, the entire SCR system can be affected. Recognizing the warning signs early can help prevent further aftertreatment issues.
One of the most common indicators is an illuminated check engine or emissions warning light.
Other common signs of a bad DEF doser injector include:
- SCR or DEF system fault codes
- Reduced engine operation or speed limitation
- Excessive DEF consumption
- White crystallized buildup around the injector area
- Strong ammonia-like exhaust odor
- Failed emissions testing
Crystallization is a frequent cause of trouble. DEF can harden when exposed to air or high temperatures, restricting the injector nozzle and disrupting proper spray patterns.
Electrical failure is another possibility. Damaged wiring or an internal solenoid issue can prevent the injector from operating correctly.
In some cases, poor spray patterns can lead to uneven dosing, which may trigger NOx sensor or catalyst efficiency codes.
Because multiple components work together in the SCR system, proper diagnosis is essential. A technician will scan for fault codes, test injector activation, and inspect for buildup to confirm whether the DEF doser injector is the source of the problem.
Addressing the issue quickly helps protect the entire emissions system.
The Cummins 4387109 DEF Doser Injector meters Diesel Exhaust Fluid into the exhaust system to support emissions control.
The Cummins 4387109 DEF Doser Injector is mounted in the exhaust stream ahead of the SCR catalyst.
Common signs include SCR fault codes, increased DEF usage, or emissions system warnings.
Yes, the Cummins 4387109 is designed to interface with the engine’s original DEF and SCR monitoring systems.
Cummins DEF Doser Injectors
