BorgWarner 4735-44003-12 Engine Cooling Fan Blade

The BorgWarner 4735-44003-12 is a 32-inch diameter engine cooling fan blade engineered for heavy-duty Class 8 truck applications. It features 11 clockwise (CW) rotation blades constructed from high-strength glass-filled nylon composite for durability and thermal stability. The blade mounts via a 2.56-inch (65 mm) pilot diameter and a 3.5-inch (89 mm) bolt circle pattern, ensuring precise alignment with the fan clutch or hub assembly. This component serves as a direct replacement for the BorgWarner Kysor 4735 series fan blades used across multiple OEM truck platforms including Peterbilt, Kenworth, Freightliner, International, Western Star, Volvo, and Mack. It is compatible with engines such as Cummins ISX15, Caterpillar C13/C15, Detroit Diesel DD13/DD15, Volvo D13, and Mack MP8. The lightweight composite construction reduces rotational inertia while maintaining structural integrity under high-RPM operating conditions.