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Cummins QSB 4.5L Turbo Assembly 2017-2023: OEM 5321673RX

CUMMINS QSB 4.5L TURBO ASSEMBLY 2017-2023: OEM 5321673RX

Shipping ICON

ORDERS PLACED BEFORE 3PM EST WILL SHIP SAME DAY

WARRANTY ICON

WARRANTY
1M MILES OR 1 YEAR

$5,850.00

CORE CHARGE:

$2,000.00
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 NUMBER5321673RX
PART TYPETurbo Assembly
BRANDCummins Holset
ENGINE MAKECummins
ENGINE TYPEQSB 4.5L
YEAR2017-2023
PART NUMBER5321673NX-WA
APPLICATION NOTESTier 4

PRODUCT DESCRIPTION

This is a New, Cummins Holset Turbo Assembly, Cummins Holset part number 5321673NX-WA ( OEM Part Number 5321673RX ).This part is primarily made for a Cummins QSB 4.5L, production years 2017-2023, and comes with a One Million Miles or One Year Warranty. For additional warranty info Click Here

OEM NUMBERS

Primary OEM5321673RX
Additional OEM5321673RX, 5326278

ADDITIONAL DETAILS

CONDITIONNew
UPC / Barcode00840490539518
WEIGHT27.00 LBS

SHIPPING OPTIONS

Ship Weight : 27.00 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.


Give your Cummins QSB 4.5L (2017–2023) a powerful resurgence with this Turbo Assembly — OEM 5321673RX. Built to deliver instant boost and responsive torque, this rugged turbo keeps your engine sharp, efficient, and ready for heavy demands. Engineered to match exacting OEM standards for a flawless drop-in fit, it’s the elite choice for peak performance, mile after mile.

FITMENT CHART

YEARMAKEENGINE(S)
2017Cummins QSB 4.5L
2018Cummins QSB 4.5L
2019Cummins QSB 4.5L
2020Cummins QSB 4.5L
2021Cummins QSB 4.5L
2022Cummins QSB 4.5L
2023Cummins QSB 4.5L

PEOPLE ALSO ASKS | BLOG(S)

When your Cummins QSB 4.5L engine is due for a turbo replacement, choosing the proper part is essential. The OEM 5321673RX Turbo Assembly ensures precision-built performance that restores smooth airflow, dependable boost delivery, and long-term durability—all designed to help your engine perform at its best.

  • Delivers consistent, factory-spec airflow and boost pressure, reducing turbo lag and improving response under various load conditions.

  • Helps maintain ideal combustion by ensuring the engine gets a steady supply of pressurized air—supporting cleaner operation and improved fuel efficiency.

  • Prevents added strain on downstream components like the intercooler and exhaust system, promoting system balance and longevity.

  • Engineered to fit Cummins QSB 4.5L engines seamlessly—no extra parts, no guesswork, just a reliable plug-and-play installation.

  • Backed by warranty coverage and easy core return service, providing confidence and cost-efficient maintenance planning.

A well-functioning turbo is critical to engine performance and resilience. With the OEM 5321673RX, you’re installing a component that delivers authentic fit, steady performance, and peace of mind—all in one dependable package.

A turbocharger plays a key role in boosting engine efficiency by forcing more air into the combustion chamber. However, like any component subjected to heat, pressure, and motion, it can wear out or fail over time. Understanding what causes a turbo assembly to go bad can help prevent breakdowns and costly repairs.

Common Causes of Turbo Assembly Failure

  • Oil Contamination or Starvation
    Turbos rely heavily on clean, uninterrupted oil flow. Dirty oil or low oil pressure can damage the turbo’s bearings and other moving parts.

  • Foreign Object Damage
    Debris entering the air intake or exhaust system can strike the turbo’s blades, leading to severe internal damage or imbalance.

  • Excessive Exhaust Temperatures
    High temperatures, especially during heavy engine load or insufficient cool-down periods, can warp or crack turbo components.

  • Boost Pressure Issues
    Overboosting due to a faulty wastegate or tuning can put excessive strain on the turbo, increasing the risk of failure.

  • Poor Maintenance Practices
    Skipping oil changes, neglecting air filter replacements, or using incorrect oil types can all accelerate turbo wear.

  • Worn Seals or Leaks
    Oil leaks in the turbo can result in blue smoke from the exhaust and signal internal seal degradation, which impairs turbo function.


Turbocharger failure is often avoidable with consistent maintenance and early attention to warning signs like smoke, strange noises, or power loss. Regular oil changes, clean air filters, and proper shut-down practices go a long way in preserving turbo health. Taking care of your turbo means taking care of your entire engine system.

Listen for unusual whining, lag in boost, or excessive smoke during acceleration.

Engine power drops, fuel efficiency suffers, and blue or black smoke may be expelled.

Checking boost pressure consistency and inspecting for shaft play can reveal turbo condition.

Frequent oil changes and proper oil filtration help maintain bearing lubrication and longevity.

Cummins Turbo Assemblys

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