
Cummins QSB4.5L Turbo Assembly 2018-2020: OEM 5321675RX
CUMMINS QSB4.5L TURBO ASSEMBLY 2018-2020: OEM 5321675RX

ORDERS PLACED BEFORE 3PM EST WILL SHIP SAME DAY

WARRANTY
1M MILES OR 1 YEAR
PRODUCT DESCRIPTION
This is a Remanufactured Tamerx Turbo Assembly, Tamerx part number 5321675RM-WA ( OEM Part Number 5321675RX ). 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 QSB4.5L, production years 2018-2020, and comes with a One Million Miles or One Year Warranty. For additional warranty info Click Here
Additional Notes: 24 Volts
OEM NUMBERS
| Primary OEM | 5321675RX |
| Additional OEM | 5321675, 5321675RX, 5326264, 532626400H, 5326264H, 5326264HX, 5326400 |
ADDITIONAL DETAILS
| CONDITION | Remanufactured |
| UPC / Barcode | 00840490536296 |
| WEIGHT | 44.00 LBS |
SHIPPING OPTIONS
Ship Weight : 44.00 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.
Designed for Cummins QSB4.5L engines produced between 2018 and 2020, OEM 5321675RX is a turbo assembly engineered to integrate with the factory intake and exhaust system layout. This unit is manufactured to OEM specifications to ensure proper fitment and compatibility with existing engine components. Built from durable materials, it is suited for the operating temperatures and demands common in medium-duty diesel applications. The assembly supports consistent airflow management during normal engine operation. It is a reliable option for fleet service and targeted repair needs requiring dependable turbo system functionality.
FITMENT CHART
| YEAR | MAKE | ENGINE(S) | ||||
|---|---|---|---|---|---|---|
| 2018 | Cummins | QSB4.5L | ||||
| 2019 | Cummins | QSB4.5L | ||||
| 2020 | Cummins | QSB4.5L | ||||
PEOPLE ALSO ASKS | BLOG(S)
The Cummins QSB4.5L Turbo Assembly 2018–2020: OEM 5321675RX works by using exhaust energy to drive a turbine that compresses incoming air before it enters the engine. This process increases the density of the air entering the combustion chamber, allowing the engine to operate efficiently under varying load conditions.
As the engine runs, exhaust gases exit the cylinders and flow into the turbocharger’s turbine housing. The force of the exhaust spins the turbine wheel. This turbine is connected by a shaft to a compressor wheel on the intake side of the turbo.
Here’s how the turbo assembly functions step by step:
- Exhaust gases spin the turbine wheel
- The turbine shaft rotates the compressor wheel
- The compressor pulls in and compresses fresh air
- Compressed air is directed into the engine’s intake system
Many QSB4.5L turbo assemblies include a wastegate or variable geometry system to regulate boost pressure. This mechanism controls how much exhaust energy reaches the turbine, ensuring proper airflow across different engine speeds and loads.
OEM 5321675RX is engineered specifically for 2018–2020 Cummins QSB4.5L engines, ensuring correct fitment and integration with engine controls. A properly functioning turbo assembly supports consistent airflow management, stable combustion, emissions control, and reliable engine operation in industrial and equipment applications.
When your turbo assembly is failing, immediate action is critical to prevent severe engine damage and costly secondary repairs. A failing turbo can lead to oil contamination, power loss, excessive smoke, and even engine runaway if left unaddressed.
The first step is to reduce engine load and avoid continued operation under heavy acceleration or towing conditions. If you notice loud whining noises, blue or white smoke, sudden loss of power, or excessive oil consumption, stop operating the vehicle as soon as it is safe to do so.
Midway through diagnosis, focus on these essential checks:
- Inspect engine oil level and condition
- Check turbo oil feed and return lines for restriction or leaks
- Inspect for excessive shaft play or oil leakage at the turbo
- Scan for underboost or overboost fault codes
- Check for boost leaks in charge air piping
- Inspect DPF or exhaust system for restriction
If bearing damage or oil seal failure is confirmed, turbo replacement is typically required. However, replacing the turbo without correcting the root cause—such as oil starvation, injector over-fueling, crankcase pressure issues, or exhaust restriction—will likely result in repeat failure.
Before installing a new turbo, flush or replace contaminated oil lines, change the engine oil and filter, and inspect the intercooler for oil accumulation. Proper diagnostics, lubrication system verification, and correction of contributing engine issues are essential to restoring performance and preventing future turbo assembly failure.
New gaskets, seals, and correct oil line fittings are generally required to ensure proper sealing and lubrication.
Yes, professional installation is recommended to ensure correct alignment, connections, and torque specifications.
It is used in medium-duty trucks, commercial vehicles, and industrial equipment equipped with compatible QSB4.5L engines.
Inspection and cleaning of the oil feed and return passages are advised before installation to ensure proper lubrication.































































































