3939353
Rear Cover Gasket
Cummins®

Introduction

The Cummins 3939353 Rear Cover Gasket is a critical component for heavy-duty truck engines, designed to ensure a secure seal between the engine’s rear cover and the block. This seal is essential for maintaining the integrity of the engine’s oil system, preventing oil leaks, and contributing to the engine’s overall efficiency and reliability ¹.

Function and Operation

This part creates a tight seal that prevents oil from escaping the rear cover of the engine. Maintaining proper oil levels and pressure is necessary for lubricating moving parts and cooling the engine. The gasket is positioned between the rear cover and the engine block, compressing to form a barrier against oil leakage ².

Key Features

The 3939353 is constructed from materials that offer durability and resistance to high temperatures and pressures. Its design specifications are tailored to fit precisely within the engine’s rear cover assembly, ensuring a snug fit that enhances sealing effectiveness. Unique characteristics may include reinforced edges to withstand the rigors of engine operation and a composition that resists degradation over time ³.

Benefits

Using the Rear Cover Gasket in heavy-duty truck engines offers several benefits. It contributes to improved engine efficiency by maintaining optimal oil levels and pressure. Additionally, by preventing oil leaks, it reduces the need for frequent maintenance, leading to lower maintenance costs. The gasket also enhances the reliability of the engine, ensuring consistent performance under demanding conditions.

Installation Process

Installing the Cummins 3939353 requires careful preparation and attention to detail. Before installation, the mating surfaces of the rear cover and engine block should be cleaned to remove any debris or old gasket material. The gasket should be positioned correctly within the rear cover, ensuring it is not twisted or misaligned. During reassembly, it is important to follow the manufacturer’s torque specifications for tightening bolts to avoid over-tightening, which could damage the gasket, or under-tightening, which could lead to leaks.

Common Issues and Troubleshooting

Common issues with Rear Cover Gaskets include leaks or failure due to wear, improper installation, or damage. Troubleshooting these problems involves inspecting the gasket for signs of wear or damage, checking the fit and alignment within the rear cover, and ensuring that the mating surfaces are clean and free of debris. Addressing these issues promptly can prevent more significant engine problems and ensure the gasket continues to perform its sealing function effectively.

Maintenance Tips

To ensure the longevity and optimal performance of the Rear Cover Gasket, regular inspections are recommended. This includes checking for signs of wear or damage during routine engine maintenance. Cleaning the gasket and mating surfaces as part of the maintenance routine can also help prevent issues related to debris or contamination. Replacement guidelines should be followed to ensure the gasket is replaced before it reaches the end of its service life, maintaining the seal’s integrity and the engine’s efficiency.

Manufacturer Overview - Cummins

Cummins Inc. is a global power leader that designs, manufactures, and distributes engines, filtration, and power generation products. With a strong reputation in the automotive and heavy-duty truck industries, Cummins is known for its commitment to producing high-quality engine components. The company’s extensive experience and innovation in engine technology contribute to the reliability and performance of its products, including the 3939353.

Compatibility with Cummins Engines

The 3939353 is designed to fit a variety of Cummins engines. This gasket is crucial for sealing the rear cover of the engine, ensuring that there are no leaks and that the engine operates efficiently.

Compatible Engines

6 Series Engines

• 6B5.9
• 6C8.3
• C GAS PLUS CM556
• C8.3 G
• G8.3
• G8.3 CM558
• GTA8.3 CM558

ISC Series Engines

• ISC CM2150
• ISC CM554
• ISC CM850
• ISC8.3 CM2250

ISL Series Engines

• ISL CM2150
• ISL CM554
• ISL G CM2180
• ISL9 CM2150 SN
• ISL9 CM2250
• ISL9.5 CM2880 L138

L Series Engines

• L GAS PLUS CM556
• L8.9
• L8.9 CM2670 L134C
• L8.9 L121
• L8.9G CMOH2.0 L125B
• L9 CM2670 L128B
• L9.3 L105
• L9.5 L117

It is important to verify the specific engine model and configuration when selecting this gasket to ensure compatibility and proper fitment.

Role in Engine Systems

The Rear Cover Gasket, identified by part number 3939353, is crucial for ensuring the integrity and efficiency of various engine systems. Its primary function is to create a seal between the rear cover of the engine and adjacent components, preventing leaks and maintaining system pressure.

Integration with Engine Components

1. Flywheel Housing and Mounting: The Rear Cover Gasket is positioned between the flywheel housing and the engine block. This seal is vital for maintaining the structural integrity of the flywheel housing mounting. It ensures that no fluids or gases escape, which could lead to inefficient operation or damage to the flywheel.

2. Gasket Kit and Lower Engine Gasket Kit: When utilizing a gasket kit or a lower engine gasket kit, the Rear Cover Gasket plays a significant role. It complements other gaskets within these kits to ensure a comprehensive seal across the engine’s lower section. This is particularly important during engine installation or overhaul processes.

3. Rebuild Kit and Overhaul Kit: In the context of a rebuild kit or an overhaul kit, the Rear Cover Gasket is a fundamental component. It ensures that all refurbished or replaced parts within the engine function within a sealed environment. This enhances the durability and performance of the engine post-overhaul.

4. Radiator Mounting and On-Board Spares Kit: Although indirectly related, the effectiveness of the Rear Cover Gasket influences the overall engine health, which in turn affects components like the radiator mounting. Ensuring a sealed engine environment helps maintain optimal engine temperature, indirectly supporting the radiator’s function. Including this gasket in an on-board spares kit underscores its importance for maintenance and repair scenarios.

5. Tachometer Parts Kit and Upper Engine Gasket Kit: While the tachometer parts kit focuses on engine monitoring, the Rear Cover Gasket ensures the engine operates within specified parameters, providing accurate data for the tachometer. Similarly, the upper engine gasket kit works in tandem with the Rear Cover Gasket to ensure a fully sealed engine, from top to bottom, enhancing overall engine efficiency and reliability.

Conclusion

The Cummins 3939353 Rear Cover Gasket is a vital component in maintaining the sealed integrity of various engine systems, directly influencing their performance and longevity. Its proper installation, maintenance, and compatibility with specific engine models are essential for ensuring the engine’s efficiency, reliability, and overall health.