3971620
Expansion Tank
Cummins®

The Cummins 3971620 Expansion Tank is a component designed for use in the cooling systems of commercial trucks. Its primary function is to manage the changes in volume of the coolant as it heats up and cools down, ensuring the system operates efficiently and reliably.

Basic Concepts of Expansion Tanks

An expansion tank is a part of a cooling system that allows for the expansion and contraction of coolant as it undergoes thermal changes. When the engine operates, the coolant heats up and expands. Conversely, as the engine cools, the coolant contracts. The expansion tank accommodates these volume changes, maintaining system pressure and preventing coolant loss ¹.

Purpose of the Cummins 3971620 Expansion Tank

This Cummins part plays a role in the operation of a truck’s cooling system by maintaining consistent pressure within the system. It accommodates the increased volume of coolant when the engine is hot and allows coolant to return to the system when it cools down. This helps prevent coolant loss and ensures the cooling system functions effectively.

Key Features

The 3971620 Expansion Tank is constructed from durable materials that resist corrosion and withstand high temperatures. It has a specific capacity designed to handle the volume changes of the coolant in commercial truck applications. The tank features a design that enhances performance, including a robust cap that maintains system pressure and a clear sight glass that allows for easy monitoring of coolant levels.

Benefits

This part offers several advantages. It contributes to improved cooling system efficiency by ensuring consistent pressure and accommodating volume changes effectively. This can lead to extended lifespan of cooling system components and enhanced overall truck performance and reliability.

Installation Considerations

When installing this part, it is important to follow guidelines and best practices to ensure proper integration with the truck’s cooling system. This includes verifying compatibility with the specific truck model, gathering necessary tools, and following a step-by-step installation process to ensure the tank is correctly positioned and connected.

Troubleshooting and Maintenance

Common issues with expansion tanks can include leaks, pressure inconsistencies, and coolant contamination. Diagnostic tips for identifying problems include checking for visible leaks, monitoring coolant levels, and ensuring the cap is securely in place. Regular maintenance routines, such as inspecting the tank for signs of wear and ensuring the cap is functioning correctly, can help maintain optimal performance. If issues persist, considering replacement may be necessary.

Cummins Overview

Cummins Inc. is a well-established company with a strong reputation in the commercial truck industry. Founded in 1919, Cummins has a history of producing high-quality automotive components. The company is known for its commitment to innovation, reliability, and customer satisfaction, making it a trusted name in the industry.

Cummins Expansion Tank Part 3971620 Compatibility

The Cummins Expansion Tank part number 3971620 is designed to fit seamlessly with several of Cummins’ engine models. This part is integral to the cooling system, ensuring that the engine operates within optimal temperature ranges by managing coolant expansion and pressure.

Compatible Engines

• 6C8.3
• QSB5.9 CM850
• QSB6.7 M CM2250

These engines, while differing in specifications and applications, share a common requirement for effective coolant management. The expansion tank part 3971620 is engineered to meet these needs, providing a reliable solution across the listed engine models.

By ensuring proper fitment and functionality, this part helps maintain engine performance and longevity. Its compatibility with the 6C8.3, QSB5.9 CM850, and QSB6.7 M CM2250 engines underscores its versatility and importance in the engine’s cooling system.

Role of Part 3971620 Expansion Tank in Engine Systems

The 3971620 Expansion Tank is an integral component in the efficient operation of various engine systems. It works in conjunction with several key components to maintain system integrity and performance.

Interaction with Heat Exchanger

The expansion tank is designed to accommodate the changes in fluid volume within the heat exchanger system. As the engine operates, the heat exchanger transfers heat from the engine coolant to the surrounding air, causing the coolant to expand. The expansion tank provides a reservoir for this expanded coolant, preventing excessive pressure build-up within the system. This ensures consistent and efficient heat transfer, contributing to the overall thermal management of the engine ².

Integration with Plumbing System

In the plumbing system, the expansion tank plays a vital role in maintaining fluid dynamics. It helps regulate the pressure within the coolant lines, ensuring a smooth and uninterrupted flow of coolant throughout the engine. This is particularly important in systems where the plumbing layout includes multiple loops or branches, as it helps balance the pressure across different sections of the system.

Coordination with Keel Cooler

The keel cooler, often used in marine applications, relies on a stable and pressurized coolant system to effectively dissipate heat from the engine. The expansion tank assists in maintaining this stability by absorbing excess coolant and releasing it back into the system as needed. This dynamic balance is essential for the keel cooler to operate efficiently, ensuring that the engine remains within optimal temperature ranges even under demanding conditions.

Overall System Contribution

By interacting with these components—heat exchanger, plumbing system, and keel cooler—the 3971620 Expansion Tank ensures that the engine system operates smoothly and efficiently. It helps maintain pressure equilibrium, supports consistent heat exchange, and contributes to the reliable performance of the entire engine system.

Conclusion

The Cummins 3971620 Expansion Tank is a critical component in the cooling systems of commercial trucks. Its role in managing coolant volume changes, maintaining system pressure, and ensuring efficient heat transfer is essential for the reliable operation of the engine. Proper installation, regular maintenance, and understanding its interaction with other engine components are key to maximizing its benefits and ensuring the longevity and performance of the cooling system.