3900956
Expansion Plug
Cummins®

Introduction

The Expansion Plug 3900956, manufactured by Cummins, is a critical component in the commercial truck industry. Designed for use in various truck systems, this part ensures the integrity and efficiency of the vehicle’s operations. Cummins, a renowned name in the industry, is known for producing reliable and high-quality parts that contribute to the smooth functioning of commercial vehicles ¹.

Basic Concepts of Expansion Plugs

An expansion plug is a device used to seal openings in systems such as cooling, fuel, and other fluid-carrying components. It functions by expanding to fill the space it occupies, creating a tight seal that prevents leaks and maintains system pressure. In automotive and industrial settings, expansion plugs are essential for ensuring systems operate efficiently and safely by preventing the escape of fluids and gases ².

Role of the 3900956 Expansion Plug in Truck Operation

The 3900956 Expansion Plug is designed to fit into designated openings within a truck’s system. Its primary function is to seal these openings, maintaining the integrity of the system. This could include sealing coolant passages, fuel lines, or other critical areas where fluid containment is necessary. By ensuring a tight seal, the plug helps maintain system pressure and prevents leaks, which can lead to system failure or inefficiency ³.

Key Features

The 3900956 Expansion Plug is constructed from materials that offer durability and resistance to the high temperatures and pressures found in commercial truck environments. Its design includes features that allow it to expand and contract slightly with temperature changes, ensuring a consistent seal over time. Additionally, the plug may have unique characteristics, such as a special coating or threading, that enhance its performance and longevity in demanding applications.

Benefits

The use of the 3900956 Expansion Plug in truck operations offers several benefits. It contributes to improved system integrity by ensuring that fluids and gases remain contained within their designated pathways. This containment helps maintain system pressure and efficiency. Furthermore, by preventing leaks, the plug enhances safety, reducing the risk of accidents caused by fluid loss. Its design and material composition also contribute to increased durability, ensuring long-term performance and reliability in commercial truck applications.

Troubleshooting and Maintenance

Common issues with expansion plugs may include leaks due to improper installation, damage from high temperatures, or degradation over time. To address these issues, it is recommended to inspect the plug regularly for signs of wear or damage. If a leak is detected, the plug should be removed and replaced with a new one to ensure a tight seal. Proper maintenance practices, such as ensuring the plug is correctly installed and monitoring system pressures, can help extend the life of the 3900956 Expansion Plug and maintain optimal performance.

Compatibility of Expansion Plug 3900956 with Cummins Engines

The Expansion Plug 3900956 is designed to fit a wide range of Cummins engines. This part is crucial for maintaining the integrity of the engine’s cooling system by preventing leaks and ensuring proper thermal expansion. Below is a detailed breakdown of the engines with which this expansion plug is compatible:

• 4B3.9 and 6B5.9 Engines: Known for robust performance and reliability, often used in heavy-duty applications.
• B3.9 G and B4.5 Engines: Part of Cummins’ lineup of smaller, yet powerful engines, used in various industrial and commercial applications.
• B4.5 CM2350 B129B and B4.5 RGT Engines: Designed for high-performance applications, providing excellent fuel efficiency and power.
• B5.6 CM2670 B152B and B5.9 CM2670 B166C Engines: Part of Cummins’ mid-range power series, offering a balance of power and efficiency.
• B5.9 G and B5.9 GAS PLUS CM556 Engines: Designed for heavy-duty applications, providing reliable performance in demanding environments.
• B6.7 Series Engines: Including B6.7 CM2350 B135B, B6.7 CM2670 B153B, B6.7 CM2670 B164C, B6.7 G CMOH6.0 B125, and B6.7S, part of Cummins’ high-performance lineup.
• C GAS PLUS CM556 and D4.0 CM2620 D103B Engines: Designed for specific applications, providing reliable performance and efficiency.
• F Series Engines: Including F2.8 CM2620 F135B, F3.8 CM2350 F120B, F3.8 CM2350 F128C, F3.8 CM2620 F137B, F3.8 F102, F4.5 CM2620 F139B, and F4.5 CM2620 F141C, part of Cummins’ lineup of smaller engines.

Role of Part 3900956 Expansion Plug in Engine Systems

The Expansion Plug 3900956 is an essential component in various engine systems, contributing to the overall functionality and efficiency of the engine. Here’s how it integrates with different components:

• Accessory Drive: Manages thermal expansion within the drive components, enhancing longevity and reliability.
• Air Heater Starting Aid: Maintains consistent pressure and temperature, ensuring reliable engine starts in cold conditions.
• Block Short and Short 4BTA: Seals off unused passages within the engine block, preventing coolant leaks and maintaining engine integrity.
• Block, Short 6-BT and Short 6B Block: Closes off unnecessary openings, preserving structural integrity and preventing fluid leakage.
• Coolant Bypass Kit: Regulates coolant flow, ensuring efficient temperature management and preventing overheating.
• Crankcase Breather: Maintains pressure equilibrium within the crankcase, preventing the buildup of harmful gases.
• Crankshaft and Bearings: Manages thermal expansion, reducing bearing wear and ensuring smooth crankshaft operation.
• Cylinder Block Hardware Kit and Cylinder Block Kit: Seals off unused passages, ensuring the cylinder block remains intact and functions efficiently.
• Cylinder Short Block and Cylinder Top Level Assembly Head: Maintains structural integrity by sealing off unnecessary openings.
• Engine Block and Engine Heater: Seals off coolant passages and maintains consistent pressure and temperature for reliable engine warm-up.
• Engine, Cylinder, and Front Drive Adapter: Ensures proper sealing of components, preventing fluid leaks and maintaining structural integrity.
• Intake Air Heater: Ensures consistent pressure for efficient air heating, contributing to better engine performance in cold-start conditions.
• Long Block and Lower Engine Gasket Kit: Seals off passages and prevents fluid leaks, ensuring efficient operation of the long block and maintaining gasket kit integrity.
• Overhaul Kit: Seals off various passages during an engine overhaul, ensuring smooth operation post-overhaul.
• Short Block Kit and Short E215/235 Block: Seals off unused openings, maintaining structural integrity and efficient operation of the short block.
• Short, Block 6-BT, and Spacer Connection: Ensures all passages are sealed correctly, preventing fluid leaks and maintaining structural integrity.

Conclusion

The Expansion Plug 3900956 by Cummins is a vital component in maintaining the integrity and efficiency of commercial truck systems. Its compatibility with a wide range of Cummins engines, coupled with its durable construction and reliable performance, makes it an indispensable part for truck operators. Regular maintenance and proper installation are key to ensuring the longevity and effectiveness of this Cummins part.