FAW Fan, Fan Clutch: A Critical Guide to Its 9 Cooling Components

Welcome to this critical technical guide on the FAW Fan, Fan Clutch assembly (Part Nos. 1308010-91W and 1313010-73A). This is the primary cooling airflow system for the FAW Jiefang CA4251P66K24T1A3E5 6×4 diesel semi-trailer tractor, essential for thermal management in all conditions.

The FAW Fan, Fan Clutch is a dual-component system. It consists of the ‘Fan Assembly’ (the physical blades that move the air) and the ‘Fan Clutch Assembly’ (the intelligent, thermostatic “brain” that decides *when* to engage the fan), providing massive cooling airflow on demand while saving fuel when cooling is not needed.

This guide is an essential resource for professional technicians, fleet managers, and parts specialists. We will deconstruct the entire FAW Fan, Fan Clutch system into its 9 serviceable components, including the fan, the viscous clutch, the mounting flange, and all the high-tensile fasteners that hold this high-RPM assembly together.

Core Component: The Fan Assembly (1308010-91W)

The first major component of the FAW Fan, Fan Clutch system is the ‘Fan Assembly’ (1308010-91W). This is the “muscle” of the operation. It is a large-diameter, multi-blade fan, typically molded from a high-strength, glass-reinforced polymer (plastic) or fabricated from steel. Its design is a complex balance of aerodynamics and efficiency.

The “pitch” and “curve” of these blades are not arbitrary. They are engineered to move the maximum volume of air (measured in CFM, or Cubic Feet per Minute) through the high-resistance radiator and intercooler cores with the least amount of noise and horsepower draw. This fan is the component that does the actual cooling work when the truck is stationary or moving at low speeds, where “ram air” from vehicle movement is not enough. The integrity of these blades is critical, as a fracture would cause a catastrophic imbalance in the FAW Fan, Fan Clutch system.

The “Brain”: Fan Clutch Assembly (1313010-73A)

The ‘Fan Clutch Assembly’ (1313010-73A) is the “brain” of the FAW Fan, Fan Clutch system. A diesel engine’s fan, if “direct-driven” (locked to the engine’s speed), would be a massive source of parasitic loss, robbing the engine of as much as 20-30 horsepower and wasting significant fuel, especially when the engine is cold or at high-speed on a highway.

This component is a **viscous fan clutch**. It is a fluid-coupling device that sits between the engine’s drive pulley and the ‘Fan Assembly’. Its job is to “clutch” (engage) the fan when cooling is needed, and “declutch” (disengage) it when it is not.

**How it Works (Internal Logic):**

1. **Disengaged (Cold):** On the front of the FAW Fan, Fan Clutch is a bi-metallic, thermostatic strip. When the air passing *through* the radiator is cool, this strip is flat. This keeps an internal valve closed. The special, high-viscosity silicone fluid inside the clutch is held in a storage reservoir, and the fan “freewheels,” spinning at a low speed (e.g., 20-30% of pulley speed) just from residual drag.
2. **Engaged (Hot):** As the truck idles or climbs a grade, the engine gets hotter, and the air passing through the radiator becomes hot. This hot air hits the bi-metallic strip, causing it to “unwind” or “bend.” This action opens the internal valve. The spinning motion of the clutch “pumps” the silicone fluid from the reservoir into a working chamber between the input (pulley-driven) and output (fan-driven) plates. This thick fluid creates an immense “fluid shear,” effectively “locking” the two plates together.

This lock-up forces the fan to spin at 80-90% of the engine’s pulley speed, drawing a massive, roaring volume of air through the radiator and cooling the engine. Once the temperature drops, the bi-metallic strip cools, the valve closes, the fluid returns to the reservoir, and the fan disengages. This “on-demand” logic is the key to both the power and efficiency of the FAW Fan, Fan Clutch.

A failure of the FAW Fan, Fan Clutch is a common maintenance issue. If the internal seal fails and the fluid leaks out, the fan will *never* engage, leading to overheating in traffic or under load. If the internal valve seizes, the fan may be *permanently* engaged, resulting in a loud “roaring” noise at all times and a noticeable loss of fuel economy and power.

The Mounting Interface: Flange and Hardware

The entire FAW Fan, Fan Clutch assembly must be mounted with perfect alignment to the engine’s drive pulley (often part of the water pump). The ‘Fan Clutch Transition Flange’ (1313063-1066) is the critical adapter component that makes this possible. This flange bolts to the engine’s pulley, and the ‘Fan Clutch Assembly’ (1313010-73A) then bolts to this flange, ensuring a perfectly concentric, balanced fit.

This mounting is achieved with two sets of high-tensile hardware, essential for securing a heavy, high-RPM component.

**1. Flange-to-Pulley Mounting:** This is accomplished using the four ‘Stud Bolts’ (CQ1201025). These studs are threaded into the engine’s pulley. The flange (1313063-1066) is placed over these studs and secured by the four ‘Hex Nuts’ (CQ34010) and four ‘Spring Gaskets’ (Q40310). The spring gaskets (lock washers) are critical, as they prevent the nuts from vibrating loose.

**2. Fan-to-Clutch Mounting:** This is accomplished using the six ‘Combination Bolts’ (CQ1461030). These bolts pass through the mounting holes of the ‘Fan Assembly’ (1308010-91W) and thread into the ‘Fan Clutch Assembly’ (1313010-73A). The six ‘Hex Nuts’ (CQ34008) and six ‘Spring Gaskets’ (Q40308) are used to secure them. *Correction:* The ‘Combination Bolt’ (CQ1461030) has a captive washer and is likely used with the nuts/gaskets to secure the fan *to* the clutch. This 6-bolt pattern provides a wide, stable clamping force for the large-diameter plastic fan, preventing it from flexing or cracking. This hardware is the most critical part of the FAW Fan, Fan Clutch for safety.

FAW Fan, Fan Clutch Parts List

The following table provides the complete, detailed breakdown of all 9 components identified in the ‘Fan, Fan Clutch’ diagram for the FAW CA4251P66K24T1A3E5 tractor. A complete service of the FAW Fan, Fan Clutch often involves replacing the clutch assembly and its mounting hardware.

Technical Specifications and Assembly Context

The specifications for the FAW Fan, Fan Clutch system are defined by its function as a high-CFM, on-demand airflow system. The entire FAW Fan, Fan Clutch assembly is designed for engine efficiency and thermal protection.