4938765
Oil Seal
Cummins®

Introduction

The Cummins 4938765 Oil Seal is a component designed for use in commercial trucks. It serves to prevent oil leakage from specific points within the engine or transmission system, thereby maintaining the integrity of the lubrication system and ensuring smooth operation of the vehicle.

Basic Concepts of Oil Seals

An oil seal, also known as a rotary shaft seal, is a mechanical device used to prevent lubricants from escaping a rotating equipment’s housing. It operates on the principle of creating a barrier between the rotating shaft and the stationary housing, using materials that can withstand the pressure and temperature of the lubricants while maintaining a tight fit around the shaft ¹.

Purpose of the Cummins 4938765 Oil Seal

This Cummins part plays a role in the operation of a truck by sealing the interface between rotating and stationary components within the engine or transmission. This seal helps to retain lubricants within the system, which is vital for reducing friction, wear, and heat generation in moving parts ².

Key Features

The Cummins 4938765 Oil Seal is characterized by its material composition, typically featuring a durable elastomer for the sealing lip and a robust metal or plastic reinforcement. Its design includes precision-engineered dimensions to ensure a snug fit and effective sealing. Additionally, it may incorporate anti-rotation features to prevent the seal from twisting during operation, which could compromise its effectiveness.

Benefits

The use of the Cummins 4938765 Oil Seal in truck operations can lead to improved efficiency due to reduced oil leakage, which in turn helps maintain optimal lubrication levels. Its design contributes to the longevity of the seal by withstanding the harsh conditions within the engine or transmission. Reliability is enhanced as the seal helps prevent contamination of the lubricant and protects internal components from damage due to oil loss ³.

Installation and Maintenance

Proper installation of this Cummins part involves ensuring the mating surfaces are clean and free from imperfections that could affect the seal’s performance. It should be seated correctly without damage to the sealing lip. Routine maintenance includes regular inspections for signs of wear or damage and replacement according to the manufacturer’s guidelines or when performance issues arise.

Troubleshooting Common Issues

Common problems with oil seals include leaks, which can be caused by wear, improper installation, or contamination. Diagnosing these issues involves visual inspection and, in some cases, pressure testing. Resolution may require cleaning or replacing the seal, ensuring that all related components are in good condition to prevent recurrence.

Cummins Corporation 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 innovation in the commercial truck industry, offering a wide range of products that meet the demanding requirements of modern transportation.

Cummins Engine Oil Seal 4938765 Compatibility

The Cummins Oil Seal part number 4938765 is designed to fit a variety of Cummins engines, ensuring a secure seal to prevent oil leaks and maintain engine efficiency. Below is a detailed overview of the engines with which this oil seal is compatible.

Compatible Engines

• B4.5 CM2350 B129B
• D4.0 CM2620 D103B
• F3.8 CM2350 F120B
• F3.8 CM2350 F128C
• F3.8 CM2620 F137B
• F3.8 F102
• F4.5 CM2620 F139B
• F4.5 CM2620 F141C
• ISB4.5 CM2350 B104
• ISF3.8 CM2220 AN
• ISF3.8 CM2220 F103
• ISF3.8 CM2350 F109
• ISF4.5 CM2220 F123
• QSF3.8 CM2350 F107
• QSF3.8 CM2880 F112

Grouping of Compatible Engines

Group 1: F3.8 Series

• F3.8 CM2350 F120B
• F3.8 CM2350 F128C
• F3.8 CM2620 F137B
• F3.8 F102
• ISF3.8 CM2220 AN
• ISF3.8 CM2220 F103
• ISF3.8 CM2350 F109
• QSF3.8 CM2350 F107

Group 2: F4.5 Series

• F4.5 CM2620 F139B
• F4.5 CM2620 F141C
• ISF4.5 CM2220 F123

Group 3: B4.5 and D4.0 Series

• B4.5 CM2350 B129B
• D4.0 CM2620 D103B

Group 4: ISB4.5 and QSF3.8 Series

• ISB4.5 CM2350 B104
• QSF3.8 CM2880 F112

This oil seal is engineered to provide a reliable seal for these engines, ensuring optimal performance and longevity.

Role of Part 4938765 Oil Seal in Engine Systems

This Cummins part is an essential component in maintaining the integrity and efficiency of various engine systems. Its primary function is to prevent the leakage of lubricating oil between moving and stationary parts within the engine.

Interaction with the Cover

The oil seal is positioned within the cover to ensure that lubricating oil remains contained within the designated pathways. This containment is vital for maintaining proper lubrication and preventing oil from contaminating other engine components.

Integration with the Front Cylinder Block

In the front cylinder block, the oil seal works to separate the lubricated areas from the non-lubricated sections. This separation helps in reducing friction and wear on the cylinder walls, thereby enhancing the overall performance and longevity of the engine.

Role in the Lower Engine Gasket Kit and Set

Within the lower engine gasket kit and set, the oil seal plays a significant role in maintaining the integrity of the gaskets. By preventing oil leakage, it ensures that the gaskets perform their sealing functions effectively, which is essential for maintaining compression and preventing coolant or oil mixing.

Function in the Pump System

The oil seal is also integral to the pump system. It ensures that the lubricating oil is delivered efficiently to all necessary components without any loss. This efficiency is key to the pump’s ability to maintain consistent oil pressure throughout the engine.

Importance in the Lubricating Oil System

In the lubricating oil system, the oil seal helps in maintaining the correct oil levels and pressure. This is essential for the effective lubrication of moving parts, reducing friction, and preventing overheating.

Contribution to the Upper Engine Gasket Kit

Finally, in the upper engine gasket kit, the oil seal assists in keeping the lubricating oil within the intended pathways. This containment is important for the gaskets to function correctly, ensuring that the upper engine components remain well-lubricated and operate smoothly.

Conclusion

The Cummins 4938765 Oil Seal is a critical component in the maintenance and operation of commercial truck engines. Its role in preventing oil leakage, ensuring proper lubrication, and protecting engine components from wear and damage is indispensable. Proper installation, maintenance, and timely replacement of this part are essential for the efficient and reliable operation of the vehicle.