CAT Caterpillar C4.4, C3.6 DEF Head Unit
CAT CATERPILLAR C4.4, C3.6 DEF HEAD UNIT
ORDERS PLACED BEFORE 3PM EST WILL SHIP SAME DAY
WARRANTY
1M MILES OR 1 YEAR
PRODUCT DESCRIPTION
This is a Remanufactured, Tamerx DEF Head Unit, Tamerx part number 1795-18-1 ( OEM Part Number 5913429 ). This part is primarily made for a Caterpillar C4.4, C3.6, and comes with a One Million Miles or One Year Warranty. For additional warranty info Click Here
Additional Notes: DEF Header, Helical Heater, 40 MICRON, 18"
OEM NUMBERS
| Primary OEM | 5913429 |
| Additional OEM | 5356924, 5913429 |
ADDITIONAL DETAILS
| CONDITION | Remanufactured |
| UPC / Barcode | 00840490541351 |
| WEIGHT | 8.00 LBS |
SHIPPING OPTIONS
Ship Weight : 8.00 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 CAT Caterpillar C4.4, C3.6 DEF Head Unit OEM 5913429 is a genuine factory component designed to ensure proper Diesel Exhaust Fluid system function in Caterpillar engines. Built to precise OEM specifications, it provides accurate fitment and reliable performance for C4.4 and C3.6 applications. By supporting emissions compliance, this unit helps maintain steady and efficient engine operation in a wide range of equipment. Its rugged construction is engineered to handle the tough demands of heavy-duty work environments, offering dependable service life. For operators, this DEF head unit delivers OEM-certified quality and trusted reliability to keep Caterpillar equipment operating smoothly.
PEOPLE ALSO ASKS | BLOG(S)
If your vehicle uses a Caterpillar C4.4 or C3.6 engine with SCR (Selective Catalytic Reduction) technology, the OEM DEF Head Unit 5913429 is a vital component in the emissions control system. This smart unit is installed on top of the DEF (Diesel Exhaust Fluid) tank and serves several critical functions to keep the system working properly.
Core Responsibilities
- Fluid Monitoring
- The head unit continuously measures the level of DEF in the tank and communicates that to the engine’s control system. This ensures the system knows when it’s time to refill.
- Temperature & Fluid Condition Sensing
- It senses the temperature of the DEF to detect freezing or excessive heat. It also monitors fluid quality so the system can detect contamination or off-spec fluid.
- Heating Support
- To prevent DEF from freezing in cold weather, the head unit includes a heater or coolant paths that help keep the fluid above its freeze threshold.
- Fluid Routing & Filtration
- The unit provides a pickup port that draws DEF into the dosing/injection system and a return path for unused fluid. It also contains a strainer or filter to keep contaminants or crystals from damaging components downstream.
- Electronic Interface & Communication
- The head unit sends sensor data — level, temperature, quality — to the vehicle’s engine control module (ECM). The ECM then uses that data to control dosing, manage alarms, or apply safeguards.
In short, the CAT OEM 5913429 head unit acts as the central monitoring, protection, and routing hub for your DEF system. It ensures fluid is available, in good condition, and usable even in extreme conditions, while feeding the control system the vital data it needs to regulate emissions.
The DEF (Diesel Exhaust Fluid) head unit is a crucial part of your emissions system. It monitors fluid level, temperature, and quality to keep your truck compliant. When the unit begins to fail, your vehicle will often show early warnings that shouldn’t be ignored.
Common Signs of a Failing DEF Head Unit
Watch for these red flags that signal the unit may be going bad:
- DEF system fault codes
- appearing on the dashboard
- Check engine light
- triggered by emissions-related problems
- Incorrect DEF readings,
- such as showing empty when the tank is full
- Premature derate countdowns
- limiting mileage or time to service
- Vehicle entering limp mode,
- restricting speed to as low as 5 mph
- Inconsistent system warnings,
- with alerts that appear and disappear
The DEF head unit sends critical data to the engine control module. When the information is inaccurate or missing, the system assumes the emissions equipment isn’t working correctly. As a safeguard, it forces driving restrictions until the issue is fixed.
A failing DEF head unit won’t get better on its own. If you notice these warning signs, schedule service or replacement immediately to avoid costly downtime and stay compliant.
It is a genuine OEM DEF head unit designed for Caterpillar C4.4 and C3.6 engines.
False DEF readings, fault codes, or warning lights may indicate unit failure.
It ensures accurate DEF monitoring so the emissions system works reliably.
Yes, a failed unit can trigger derate conditions or limit machine operation.
Caterpillar DEF Head Units
