Four Seasons 45986 Accessory Drive Belt Idler Assembly

Overview of Four Seasons Idler Assembly 45986

The Four Seasons Idler Assembly 45986 is designed to maintain proper tension and routing of the accessory drive belt in select BMW models. Engineered with durable plastic material and precise dimensions, this idler assembly supports the smooth operation of the belt system in BMW 750iL, 850Ci, 850CSi, and 850i vehicles.

• Constructed from durable black plastic for reliable performance
• Measures 4.66 inches in length with a 2.9375-inch outside diameter
• Features two mounting holes with 0.25-inch diameter for secure installation
• Designed as a back idler with a single groove and 1.0-inch belt width compatibility
• Compatible with BMW 750iL, 850Ci, 850CSi, and 850i models

Detailed Product Description and Specifications

This accessory drive belt idler assembly from Four Seasons is part of the Idler Assembly product line, which focuses on tensioners and pulleys essential for maintaining proper belt tension and alignment. The idler assembly is made from high-quality plastic, ensuring resistance to wear and heat within the engine compartment. It features an inside diameter of 1.01 inches and an outside diameter of approximately 2.94 inches (74.6 mm), with a pulley width of 0.94 inches (23.9 mm). The assembly includes two mounting holes, each with a diameter of 0.25 inches, designed for secure attachment to the engine block or bracket. This part is specifically engineered as a back idler for accessory drive belt systems, compatible with a belt width of 1.0 inch (25.4 mm) and a single groove configuration.

Compatible Vehicles and Applications

The Four Seasons Idler Assembly 45986 is compatible with the following BMW models:

• BMW 750iL
• BMW 850Ci
• BMW 850CSi
• BMW 850i

This idler assembly is designed to work within the accessory drive belt system of these vehicles, ensuring proper belt tension and routing for optimal engine accessory performance.

Common Issues Addressed by This Idler Assembly

• Eliminates belt slippage caused by worn or loose idler pulleys
• Prevents premature belt wear due to misalignment
• Reduces noise from squealing or chirping belts
• Maintains consistent belt tension for accessory components
• Helps avoid engine overheating by supporting proper belt-driven cooling system operation

Installation Notes and Tips

• Ensure the engine is cool before beginning installation
• Verify the mounting hole alignment matches the vehicle’s bracket
• Use proper torque specifications for mounting bolts to avoid damage
• Inspect the accessory drive belt for wear and replace if necessary during installation
• Confirm belt routing matches manufacturer specifications after installation

Quality Assurance and Warranty

Four Seasons Idler Assembly 45986 is manufactured to meet OEM standards for fit, form, and function. The plastic construction is engineered for durability under typical engine operating conditions. While specific warranty details are not provided here, Four Seasons products generally come with a limited warranty against defects in material and workmanship. Always consult product documentation or contact the manufacturer for exact warranty terms.