3934817
Belt Tensioner
Cummins®

The Cummins 3934817 Belt Tensioner is a component designed to maintain the proper tension of belts within the engine system of commercial trucks. Its role is significant in ensuring the efficient operation of various engine accessories, contributing to the overall performance and reliability of the vehicle.

Basic Concepts of Belt Tensioners

A belt tensioner is a device used in an engine system to keep belts at the correct tension. It functions by automatically adjusting the tension on the belt as it wears or stretches over time. This is important for the proper operation of the engine’s accessory drive system, which includes components such as the alternator, water pump, and air conditioning compressor. Maintaining the correct belt tension ensures these components operate efficiently and reduces the risk of belt slippage or failure ¹.

Purpose of the 3934817 Belt Tensioner

The Cummins 3934817 Belt Tensioner plays a role in the engine’s accessory drive system by ensuring that the belts driving various components are kept at the optimal tension. This helps in the efficient transfer of power from the engine to these accessories, ensuring they function correctly. Proper tensioning also contributes to the longevity of the belts and the components they drive, reducing the likelihood of unexpected failures ².

Key Features

The Cummins 3934817 Belt Tensioner is designed with several features that enhance its performance. It incorporates a durable construction using high-quality materials, ensuring it can withstand the demanding conditions within a commercial truck engine. The design includes precision-machined components to ensure smooth operation and accurate tension adjustment. Additionally, it may feature a self-adjusting mechanism that automatically maintains the correct belt tension, reducing the need for manual adjustments ³.

Benefits

Using the Cummins 3934817 Belt Tensioner offers several benefits. It contributes to improved reliability and efficiency of the engine’s accessory drive system. By maintaining the correct belt tension, it helps in reducing wear on belts and driven components, leading to longer service intervals and lower maintenance costs. Furthermore, it enhances the overall performance of the truck by ensuring that engine accessories operate at their optimal efficiency.

Installation Process

Installing the Cummins 3934817 Belt Tensioner involves several steps. First, the old tensioner, if present, should be removed. This may require loosening or removing belts to access the tensioner. Once the old tensioner is removed, the new Cummins 3934817 Belt Tensioner can be installed in its place. It is important to follow the manufacturer’s instructions for proper alignment and securing of the tensioner. After installation, belts should be rerouted and tensioned according to the vehicle’s specifications.

Troubleshooting Common Issues

Common issues with belt tensioners can include noise from the tensioner area, belt slippage, or failure of the tensioner to maintain correct belt tension. Troubleshooting steps may involve inspecting the tensioner for signs of wear or damage, checking the belt for proper tension and condition, and ensuring that the tensioner is correctly installed and aligned. In some cases, replacing the tensioner or the belt may be necessary to resolve the issue.

Maintenance Tips

Regular maintenance of the Cummins 3934817 Belt Tensioner is important for ensuring its optimal performance and longevity. This includes periodic inspection of the tensioner and belts for signs of wear or damage, ensuring that belts are properly tensioned, and addressing any issues promptly. Following the manufacturer’s recommended maintenance schedule and using high-quality replacement parts can help in maintaining the efficiency and reliability of the engine’s accessory drive system.

About Cummins

Cummins Inc. is a global power leader that designs, manufactures, and distributes engines, filtration, and power generation products. With a history of innovation and quality, Cummins has established a strong reputation in the commercial truck industry. The company offers a wide range of products designed to meet the needs of various applications, from on-highway to off-highway and industrial uses. Cummins is committed to providing reliable, efficient, and durable solutions to its customers.

Belt Tensioner 3934817 Compatibility with Cummins Engines

The Belt Tensioner part number 3934817, manufactured by Cummins, is designed to fit a variety of Cummins engines. This part plays a role in maintaining the proper tension of the engine’s serpentine belt, ensuring efficient power transfer and minimizing wear on the belt and associated components.

Compatible Engines

• 4B3.9
• 6B5.9
• 6C8.3
• B5.9 GAS PLUS CM556
• C GAS PLUS CM556
• C8.3 G
• G5.9
• G5.9 CM558
• ISB5.9G CM2180

The Belt Tensioner 3934817 is engineered to provide a secure fit and reliable performance across these engine models. Its design ensures compatibility with the specific mounting points and belt paths of each engine, allowing for seamless integration and optimal functionality.

Role of Part 3934817 Belt Tensioner in Engine Systems

The 3934817 Belt Tensioner is an integral component in maintaining the optimal performance of various engine systems. It ensures that the drive belts, which connect to components such as the alternator and other auxiliary systems, are kept under the correct amount of tension.

When the Belt Tensioner is properly engaged, it applies the necessary force to the drive belt, preventing slippage and ensuring efficient power transmission from the engine to the alternator. This consistent tension is vital for the alternator to generate electricity effectively, which is essential for powering the vehicle’s electrical systems and recharging the battery.

Additionally, the Belt Tensioner plays a role in the longevity and reliability of the drive components. By maintaining proper belt tension, it reduces wear and tear on the alternator drive and other connected systems, thereby enhancing the overall durability of the engine setup.

Conclusion

In summary, the 3934817 Belt Tensioner is a key element in the symbiotic relationship between the engine and its auxiliary components, ensuring smooth operation and prolonged service life.