3900955
Expansion Plug
Cummins®

The Cummins 3900955 Expansion Plug is a component designed for use in commercial truck operations. It serves a specific function within the truck’s engine or cooling system, contributing to the overall efficiency and reliability of the vehicle. Understanding its purpose and role is fundamental for maintaining and optimizing truck performance.

Basic Concepts of Expansion Plugs

Expansion plugs are mechanical devices used to seal openings in various systems, including automotive and industrial applications. They function by expanding within a hole to create a tight seal, preventing the passage of fluids or gases. This sealing capability is crucial in maintaining system integrity and preventing leaks, which can lead to operational inefficiencies or failures ¹.

Purpose of the Cummins 3900955 Expansion Plug

The Cummins 3900955 Expansion Plug plays a role in the operation of a truck by sealing specific openings within the engine or cooling system. Its function is to maintain system pressure and prevent the escape of fluids or gases, which is vital for the efficient operation of the truck. By ensuring a secure seal, it contributes to the overall reliability and performance of the vehicle ².

Key Features

The Cummins 3900955 Expansion Plug is characterized by its material composition and design attributes. It is typically made from durable materials that can withstand high temperatures and pressures, ensuring longevity and reliability. Its design allows for easy installation and removal, facilitating maintenance procedures. Additionally, it may possess unique characteristics that enhance its sealing capabilities, such as a specialized expansion mechanism.

Benefits

Utilizing the Cummins 3900955 Expansion Plug offers several advantages. It contributes to improved system integrity by providing a reliable seal, which helps maintain operational efficiency. Its durable construction ensures longevity, reducing the need for frequent replacements. Furthermore, by preventing leaks, it enhances the overall performance and reliability of the truck.

Installation Process

Proper installation of the Cummins 3900955 Expansion Plug involves several steps. First, the opening where the plug will be installed must be clean and free of debris. Using the appropriate tools, the plug is then inserted into the opening and expanded to create a secure seal. It is important to follow manufacturer guidelines to ensure correct installation and optimal performance.

Troubleshooting Common Issues

Typical problems associated with expansion plugs include leaks and improper sealing. Diagnosing these issues may involve inspecting the plug for signs of damage or wear and checking the surrounding area for leaks. Recommended solutions may include replacing the plug or adjusting its position to ensure a proper seal. Regular maintenance and inspection can help prevent these issues.

Maintenance Tips

To ensure the longevity and optimal performance of the Cummins 3900955 Expansion Plug, regular maintenance practices are recommended. This includes inspecting the plug for signs of wear or damage and ensuring it remains securely in place. Following manufacturer guidelines for maintenance schedules and care instructions will help maintain system integrity and operational efficiency.

Cummins Overview

Cummins Inc. is a global power leader that designs, manufactures, and distributes engines, filtration, and power generation products. With a history spanning over a century, Cummins has established a reputation for quality and reliability in the commercial truck industry. Its product range includes engines, powertrain components, and aftermarket parts, all designed to meet the demanding requirements of commercial operations.

Compatibility of Cummins Expansion Plug Part 3900955 with Various Engine Models

The Cummins Expansion Plug part number 3900955 is designed to fit a wide range of Cummins engine models. This part is crucial for maintaining the integrity of the engine’s cooling system by preventing leaks and ensuring proper sealing. Below is a detailed breakdown of the engine models that are compatible with this expansion plug:

Small Bore Engines

• 4B3.9
• 6B5.9
• B3.9 G
• B4.5
• B4.5 RGT
• B5.6 CM2670 B152B
• B5.9 CM2670 B166C
• B5.9 G
• B5.9 GAS PLUS CM556
• G5.9
• G5.9 CM558

Medium Bore Engines

• B6.7 CM2350 B135B
• B6.7 CM2670 B153B
• B6.7 CM2670 B164C
• B6.7 G CMOH6.0 B125
• B6.7S
• F2.8 CM2620 F135B

Large Bore Engines

• 6C8.3
• C8.3 G
• G8.3

Industrial and Marine Engines

• ISB CM2150
• ISB CM550
• ISB CM850
• ISB/ISD4.5 CM2150 B119
• C GAS PLUS CM556

This expansion plug is engineered to provide a reliable seal in various operating conditions, ensuring the longevity and efficiency of the engine. It is essential to verify the compatibility of this part with the specific engine model to ensure proper fit and function.

Role of Part 3900955 Expansion Plug in Engine Systems

The part 3900955 Expansion Plug is integral to the functionality and maintenance of various engine systems. Its application spans across multiple components, ensuring optimal performance and safety.

Block and Short Engine Configurations

In the block and various short engine configurations such as the Short E3 Incent, Short Euro1, Short 6-B Block, Short 6B Block, Short Block, Short E2 Block, and Short Engine Kit, the Expansion Plug is used to seal unused passages. This prevents coolant or oil leakage, maintaining the integrity of the engine’s fluid systems.

Crankshaft and Bearings

When installed in the crankshaft and bearings setup, the Expansion Plug helps in blocking off unnecessary oil passages. This ensures that the oil supply is directed efficiently to the critical bearing surfaces, enhancing lubrication and reducing wear.

Cylinder Block Kit and Engine Block

In the cylinder block kit and engine block, the Expansion Plug is employed to close off drillings that are not required for specific engine models or modifications. This customization allows for a tailored fit, improving the engine’s overall performance and reliability.

Flywheel Housing and Gear Housing

Within the flywheel housing and gear housing, the Expansion Plug seals off passages that could allow fluid contamination or leakage. This is particularly important in maintaining the precision and efficiency of gear operations.

Fuel System Components

For the fuel connector adapter and fuel plumbing, the Expansion Plug ensures that fuel lines are correctly sealed, preventing any fuel leaks that could pose a safety hazard. It also aids in maintaining the correct fuel pressure within the system.

Injector and Turbocharger Plumbing

In the injector system and turbocharger plumbing, the Expansion Plug is used to block off ports that are not in use. This ensures that the fuel and air mixture is delivered accurately and that the turbocharger operates within its designed parameters.

Oil Pan and Retrofit Kits

The oil pan and various retrofit kits such as the Oil Pan Retrofit Kit and Repto Kit utilize the Expansion Plug to seal off old or unnecessary oil passages. This is vital for preventing oil leaks and ensuring that the oil pan functions correctly with the new configuration.

Performance Parts and Service Blocks

In performance parts and service blocks, the Expansion Plug is often used to customize the engine for enhanced performance. By sealing off specific passages, it allows for better control over fluid dynamics within the engine, contributing to improved efficiency and power output.

Railcar Installation Package

In the context of a railcar installation package, the Expansion Plug ensures that all fluid systems are correctly sealed, which is essential for the safe and efficient operation of railcar engines. This is particularly important in environments where maintenance access is limited.

The Expansion Plug, part 3900955, plays a versatile role across these engine systems, contributing to their efficiency, safety, and reliability.

Conclusion

The Cummins 3900955 Expansion Plug is a vital component in the maintenance and operation of commercial truck engines. Its role in sealing various engine systems ensures the integrity, efficiency, and reliability of the vehicle. Proper installation, regular maintenance, and understanding its compatibility with different engine models are essential for optimal performance. By utilizing this part, truck operators can enhance the longevity and operational efficiency of their vehicles.