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Cummins ISX15 Fuel Injector 2018-2021: OEM 5579421RX

CUMMINS ISX15 FUEL INJECTOR 2018-2021: OEM 5579421RX

Shipping ICON

ORDERS PLACED BEFORE 3PM EST WILL SHIP SAME DAY

WARRANTY ICON

WARRANTY
1M MILES OR 1 YEAR

$595.00

CORE CHARGE:

$250.00
iCORE DISCLAIMER: The CORE charge is a 30 day hold and will not be processed as long as the CORE is returned within 30 days. If you do not have a CORE or fail to return the CORE within 30 days, the CORE charge hold amount will be processed at that time.

AVAILABILITY IN STOCK
OEM NUMBER5579421RX
PART TYPEFuel Injector
BRANDOEX Reman
ENGINE MAKECummins
ENGINE TYPEISX15
YEAR2018-2021
PART NUMBER5579421RI
ADDITIONAL NOTESOEX Reman- Inlcudeds injector and Fuel Connector
FILE ATTACHMENTS OEX REMAN

PRODUCT DESCRIPTION

This is a Remanufactured OEX Reman Fuel Injector, OEX Reman part number 5579421RI ( OEM Part Number 5579421RX ). 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 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 OEM5579421RX
Additional OEM4327147, 5579421, 5579421RX

ADDITIONAL DETAILS

CONDITIONRemanufactured
UPC / Barcode00840490538269
WEIGHT1.00 LBS

SHIPPING OPTIONS

Ship Weight : 1.00 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.


Reliable fuel delivery is achieved with the Cummins ISX15 Fuel Injector 2018-2021: OEM 5579421RX, a direct-fit replacement for compatible ISX15 diesel engines. Built to OEM standards, this injector provides accurate fit and consistent operation to support proper combustion and steady engine performance. Its durable design ensures long-term dependability in demanding conditions, helping protect the fuel system and overall engine efficiency. By choosing an OEM injector, you reduce the risk of compatibility concerns and promote lasting reliability. This component is a dependable option for keeping Cummins-powered trucks operating smoothly and efficiently.

FITMENT CHART

YEARMAKEENGINE(S)
2018Cummins ISX15
2019Cummins ISX15
2020Cummins ISX15
2021Cummins ISX15

PEOPLE ALSO ASKS | BLOG(S)

When your truck relies on a Cummins ISX15 engine made between 2018 and 2021, the OEM 5579421RX fuel injector kit (which includes six injectors and fuel connector tubes) plays a pivotal role in maintaining engine performance and efficiency.

Core Purpose of These Injectors:

  • Deliver Precise Fuel Doses
    • Each injector is tasked with delivering the exact amount of diesel into its corresponding cylinder at the precise moment dictated by the engine control system. This precision supports efficient combustion and consistent power delivery.
  • Ensure Optimal Atomization
    • By transforming liquid fuel into micro-fine droplets, the injectors promote thorough air-fuel mixing—resulting in more complete combustion, lower soot, and improved fuel efficiency.
  • Enable Engine Durability and Reliability
    • Remanufactured to meet or exceed OEM standards, these injectors include fuel connector tubes and come with a robust warranty (often one million miles or one year), offering peace of mind over time.

These injectors are not merely replacements—they’re certified, calibrated components that help your engine run cleaner, more efficiently, and with greater consistency. Proper injector performance means smoother idle, stronger throttle response, and reduced downtime.

In short, the 5579421RX injector kit ensures your ISX15 engine stays at peak performance—handling everything from fuel economy to emissions and uptime with precision.

Fuel injectors are built to last, but like any mechanical component, they wear over time. Their main job is to deliver fuel into the engine’s cylinders in a fine spray. When they work correctly, they help maintain smooth operation and efficiency.

Typical Lifespan of Fuel Injectors

On average, fuel injectors last between 80,000 to 150,000 miles. However, this range can vary based on:

  • Fuel quality
    • Clean, filtered fuel extends life
  • Driving habits
    • Stop-and-go traffic and short trips can increase wear
  • Engine condition
    • Oil or coolant leaks can contaminate the injector system
  • Maintenance
    • Timely filter changes and use of fuel system cleaners help prevent buildup

You may notice rough idling, poor fuel economy, or starting trouble as injectors begin to fail. Early signs often appear gradually, so regular inspections can help detect issues before they lead to bigger problems.

With proper care and clean fuel, injectors can serve you well for many miles. Regular maintenance is the key to maximizing their lifespan and avoiding unexpected repairs.

It delivers precise amounts of diesel fuel into the combustion chamber of ISX15 engines.

Bad injectors may lead to misfires, poor fuel economy, smoke, or engine fault codes.

Yes, calibration during installation is recommended for precise fuel control.

Yes, running with bad injectors can cause piston damage or internal engine wear.

Cummins Fuel Injectors

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