
Cummins ISX15 Fuel Injector 2018-2021: OEM 5579421RX ( Set of 6 )
CUMMINS ISX15 FUEL INJECTOR 2018-2021: OEM 5579421RX ( SET OF 6 )

ORDERS PLACED BEFORE 3PM EST WILL SHIP SAME DAY

WARRANTY
1M MILES OR 1 YEAR
PRODUCT DESCRIPTION
This is a Remanufactured, OEX Reman Fuel Injector, OEX Reman part number 5579421RI-SET ( OEM Part Number 5579421RX ).This part is primarily made for a Cummins ISX15, production years 2018-2021, and comes with a One Million Miles or One Year Warranty. For additional warranty info Click Here
Additional Notes: OEX Reman- Inlcudeds injector and Fuel Connector
OEM NUMBERS
Primary OEM | 5579421RX |
Additional OEM | 4327147, 5579421, 5579421RX |
ADDITIONAL DETAILS
CONDITION | Remanufactured |
UPC / Barcode | 00840490538276 |
WEIGHT | 6.00 LBS |
SHIPPING OPTIONS
Ship Weight : 6.00 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.
The Cummins ISX15 Fuel Injector 2018-2021: OEM 5579421RX (Set of 6) delivers precise fuel flow and dependable operation for ISX15 diesel engines. Each injector is manufactured to OEM specifications, ensuring proper fit and consistent performance across all six cylinders. Built for durability, this set supports efficient combustion, smooth engine function, and long-term reliability in demanding conditions. Choosing an OEM injector set reduces compatibility concerns and helps safeguard the integrity of the fuel system. This complete package is a trusted solution for keeping Cummins-powered trucks operating smoothly and efficiently.
FITMENT CHART
YEAR | MAKE | ENGINE(S) | ||||
---|---|---|---|---|---|---|
2018 | Cummins | ISX15 | ||||
2019 | Cummins | ISX15 | ||||
2020 | Cummins | ISX15 | ||||
2021 | Cummins | ISX15 |
PEOPLE ALSO ASKS | BLOG(S)
The Cummins ISX15 Fuel Injector, OEM part number 5579421RX, is designed for ISX15 engines manufactured between 2018 and 2021. This set of six fuel injectors is a critical part of the engine's combustion system, responsible for delivering precise amounts of diesel fuel into each cylinder.
What It Does:
Each injector in the set has one primary job:
to spray a controlled, high-pressure mist of fuel into the combustion chamber at exactly the right time. This ensures clean, efficient, and powerful combustion in every cylinder.
Key Functions of the 5579421RX Injector Set:
- Provides precise fuel metering for balanced engine performance
- Atomizes diesel fuel into fine particles for cleaner combustion
- Reduces emissions and supports fuel economy
- Maintains smooth engine operation and throttle response
- Helps prevent misfires, hard starts, and excessive smoke
Remanufactured to Cummins OEM standards, this injector set typically includes new fuel connector tubes and is backed by a strong warranty.
In short, the main function of the 5579421RX injector set is to ensure your ISX15 engine runs efficiently, cleanly, and reliably—mile after mile.
A bad fuel injector may not immediately stop your vehicle, but continuing to drive with one can lead to more serious problems. Whether the issue is a clog, leak, or mechanical failure, it's important to understand the risks involved.
Risks of Driving With a Faulty Injector
Driving with a bad injector can cause several issues, including:
- Misfires
- Inconsistent fuel delivery may lead to engine stuttering
- Poor throttle response
- The engine may hesitate or lag
- Increased fuel usage
- Extra fuel may be delivered or wasted
- Rough idling
- You may notice vibration or noise at stoplights
- Engine warning lights
- Diagnostic codes can be triggered
- Potential engine damage
- Over time, a bad injector can cause internal wear or overheating
When to Stop Driving
If the engine runs rough, misfires continuously, or you smell fuel, it’s best to stop and have the vehicle inspected. While it might still run, the longer you drive with a malfunctioning injector, the greater the risk of expensive repairs.
Yes, bad injectors can lead to piston wear, engine knocking, and long-term damage.
Installing all six injectors at once ensures even fuel distribution and balanced combustion.
They precisely deliver and atomize diesel fuel to maintain efficient combustion.
Delays can lead to misfires, engine damage, and higher repair costs.