3944736
Filler Cap
Cummins®

The Cummins 3944736 Filler Cap is a component designed for use in commercial trucks. Its primary role is to seal the fuel tank, ensuring that the fuel system operates efficiently and safely. This part is integral to maintaining the integrity of the fuel system by preventing fuel spillage and contamination ¹.

Purpose and Function

The Cummins 3944736 Filler Cap serves a vital function within the fuel system of a commercial truck. It acts as a seal for the fuel tank, preventing fuel from leaking out and contaminants from entering. This cap ensures that the fuel remains clean and uncontaminated, which is crucial for the proper operation of the engine. Additionally, it plays a role in maintaining the pressure within the fuel tank, which can affect the performance of the fuel system ².

Key Features

The Cummins 3944736 Filler Cap is designed with several key features that enhance its performance and durability. It is constructed from high-quality materials that are resistant to corrosion and wear, ensuring a long service life. The cap is designed to fit securely onto the fuel tank, providing a tight seal that prevents leaks. It also features a simple yet effective design that makes it easy to use during refueling.

Benefits

The Cummins 3944736 Filler Cap offers several benefits that contribute to the overall efficiency and safety of the fuel system. By providing a secure seal, it helps to maintain the integrity of the fuel system, reducing the risk of fuel leaks and contamination. This cap also enhances safety by preventing fuel spillage, which can be a fire hazard. Additionally, its design makes it easy to use, ensuring a smooth refueling process ³.

Installation and Usage

Proper installation of the Cummins 3944736 Filler Cap is crucial for ensuring its effectiveness. To install the cap, align it with the fuel tank opening and twist it clockwise until it is securely in place. Ensure that the cap is properly seated to prevent leaks. When refueling, simply unscrew the cap counterclockwise to open it, and replace it securely after refueling is complete. Regular checks should be performed to ensure the cap remains in good condition and is properly installed.

Maintenance and Troubleshooting

To ensure the longevity and reliable performance of the Cummins 3944736 Filler Cap, regular maintenance is recommended. Inspect the cap regularly for signs of wear or damage, such as cracks or corrosion. Clean the cap and the fuel tank opening to remove any dirt or debris that could affect the seal. If the cap becomes difficult to turn or shows signs of leakage, it may need to be replaced. Addressing these issues promptly can help prevent more significant problems down the line.

Safety Considerations

When handling and using the Cummins 3944736 Filler Cap, it is important to consider safety. Ensure that the cap is properly installed to prevent fuel leaks, which can pose a fire hazard. Avoid smoking or using open flames near the fuel tank when the cap is removed. Regular inspections and maintenance of the cap can help identify potential issues before they become safety concerns.

Environmental Impact

The Cummins 3944736 Filler Cap plays a role in minimizing the environmental impact of commercial trucks by preventing fuel spills. Fuel spills can contaminate soil and water sources, making it important to have a reliable sealing mechanism in place. Additionally, proper disposal and recycling practices for the cap can further reduce its environmental footprint.

Compatibility of Cummins Part 3944736 with Various Engine Models

The Cummins part 3944736, a Filler Cap, is designed to fit seamlessly with a range of Cummins diesel engines. This filler cap is an essential component for maintaining the integrity of the fuel system by preventing contamination and ensuring proper fuel levels. Below is a detailed breakdown of the compatibility of this filler cap with various Cummins engine models:

ISB CM550 and QSB5.9 44 CM550

The ISB CM550 and QSB5.9 44 CM550 engines share similar design elements, making the part 3944736 compatible with both. This compatibility ensures that the filler cap can be used interchangeably across these engine models without any modification.

ISBE CM800

The ISBE CM800 engine, while part of the Cummins lineup, has distinct specifications and design features. The part 3944736 is specifically engineered to fit the ISBE CM800, ensuring a precise and secure fit that maintains the engine’s operational standards.

ISC CM554, ISL CM554, QSC8.3 CM554, and QSL9 CM554

The ISC CM554, ISL CM554, QSC8.3 CM554, and QSL9 CM554 engines are part of Cummins’ CM554 series, which share common design elements. The part 3944736 is designed to fit all these engines, providing a standardized solution for maintaining the fuel system’s integrity across these models.

This compatibility ensures that users can confidently replace or upgrade their filler caps across these engine models, knowing that the part 3944736 will fit and function as intended.

Role of Part 3944736 Filler Cap in Engine Systems

The 3944736 Filler Cap is an essential component in the operation and maintenance of various engine systems. It is specifically designed to interface with the cover, valve, and valve cover, ensuring the integrity and efficiency of the engine’s fuel system.

Interaction with the Cover

The Filler Cap securely attaches to the cover, forming a sealed environment that prevents fuel vapors from escaping. This seal is vital for maintaining the correct pressure within the fuel system, which in turn ensures optimal fuel delivery to the engine. The cap’s design allows for easy access when refueling, while still providing a robust barrier against contaminants and moisture that could compromise fuel quality.

Coordination with the Valve

In systems where a valve is utilized to regulate fuel flow or pressure, the 3944736 Filler Cap works in tandem to maintain system stability. The cap’s sealing properties help in sustaining the pressure required for the valve to function correctly. This synergy ensures that the valve operates within its designed parameters, contributing to the overall efficiency and reliability of the engine.

Integration with the Valve Cover

The valve cover is another component where the Filler Cap plays a significant role. By ensuring a tight seal, the cap helps in keeping the valve cover free from external elements that could lead to corrosion or contamination. This protection is essential for the longevity and performance of the valve cover and, by extension, the entire engine system. The Filler Cap’s design also facilitates easy inspection and maintenance of the valve cover, allowing for timely identification and resolution of potential issues.

Conclusion

The Cummins 3944736 Filler Cap is a critical component in the fuel system of commercial trucks, ensuring the integrity and efficiency of the system by preventing fuel leaks and contamination. Its compatibility with various Cummins engine models, coupled with its robust design and ease of use, makes it a reliable choice for maintaining the fuel system’s performance and safety. Regular maintenance and proper installation are essential to maximize the benefits of this part.