The installation and tuning of electric cooling fans in vehicles such as the 2001 Ford F-150 and LS3-powered engines can significantly improve thermal management, reduce noise, and provide greater control over engine cooling. This guide draws on user experiences, technical descriptions, and practical steps from verified sources to outline a detailed process for integrating American Volt components into such systems. The focus is on the Mark VIII fan, a 44mm/1.75 hose adapter, and a Flex-A-Lite variable speed controller, with insights into wiring, fitting, and tuning.
Overview of Electric Fan Installation
Electric fans offer a modern alternative to mechanical belt-driven fans, providing more precise temperature control and reduced parasitic engine drag. When replacing a mechanical fan with an electric one, the installation process involves several steps, including removing the old fan assembly, preparing the mounting area, and ensuring proper electrical and plumbing connections.
According to user documentation from the F150Forum, the removal of the original fan requires specific tools. A fan removal tool and a water pump holding tool are recommended, particularly for disassembling the fan assembly. These tools are often available for rental at parts stores, though users should note that they may come in separate kits, as seen at O’Reilly's. To facilitate removal, the radiator should be partially drained to allow for the removal of the upper radiator hose and overflow tank hose.
The fan and shroud are then removed after loosening the shroud screws. A practical tip shared by the forum user is using a deadblow hammer on the wrench to break the fan nut, which proved more effective than manual force.
Once the original fan is out, the next step is to install the new electric fan. The user selected a Mark VIII fan, which was mounted inside the F-150 shroud after modifying the original shroud. The modification process involved using an oscillating saw to carefully cut the shroud in stages until the fan could be centered in the opening. A large block of wood was used to balance the fan for fitting, and tape was used temporarily to secure the shroud for drilling.
This method, while somewhat ad hoc, ensured a proper fit without the need for custom fabrication, which would have been a more expensive option. The user emphasized that the best solution would involve custom fans and shrouds, but this approach was more budget-friendly and still effective.
Mounting and Plumbing the Fan
A key component in the installation is the hose adapter used to connect the temperature sensor. The user selected the 44mm/1.75 hose adapter from American Volt, which is designed to fit into the cooling system for accurate temperature readings. However, it's important to note that this adapter may not be the correct size for all vehicles. The user discovered that the adapter may actually be sized for a 46mm bulge, as indicated by the product description. This highlights the importance of verifying compatibility before installation.
Once the adapter is in hand, it must be modified to accommodate the ¼ NPT threaded temperature sensor. This requires drilling and tapping the adapter using a 7/16 drill bit. The user noted that the included clamps with the adapter were insufficient and recommended using wider 2-¼ inch clamps for a secure fit. The original clamps were discarded due to their inability to prevent leakage.
To integrate the sensor into the cooling system, the user cut a slice out of the hose to match the adapter’s width. An oscillating saw was used again for this step since the hose cutter was too small. After the hose was cut, the pieces were reassembled, and the sensor orientation was adjusted to ensure proper placement before tightening the clamps.
The user emphasized the importance of testing the system for leaks after installation. In their case, a leak was initially observed but was resolved by using the wider clamps. This step is critical to prevent coolant loss and potential engine overheating.
Controller Installation and Electrical Setup
The control of the electric fan is managed through a variable speed controller, which allows for more precise temperature regulation. The user selected the Flex-A-Lite Variable Speed Controller model 31163/107012, which provides adjustable fan speeds based on temperature readings. This controller is connected to the temperature sensor installed in the cooling system, enabling the fan to activate when the engine reaches a specific temperature.
The controller wiring process involved connecting the fan to a power source and ensuring the signal wire from the engine control module (ECM) was properly routed. According to documentation from a Corvette Forum user, the wire from the ECM (often the "Optional Fan Temperature Switch in Engine," which is a white wire) connects to the ground side of the cooling fan relay. This setup ensures that the fan activates when the ECM detects the need for cooling.
The user also described the wiring process in detail. The controller has several wire options, including black and green wires, with a caution against shorting the middle black wire to the green wire. The user selected the green (+) and outer black (-) configuration, as it provided a stable and safe connection.
One important consideration is the inrush current of the fan motor. The user measured the fan's current draw under heavy load at 34A, with an expected variation of ±10%. Inrush current, the surge of electricity when the fan starts, was measured to be over 100A. This is significantly higher than the steady-state current and must be accounted for in the relay or controller setup. Basic on/off relay systems may not handle this inrush properly and could fail or wear out quickly.
Tuning and Operational Considerations
After the fan and controller are installed, tuning is necessary to ensure the system operates efficiently. The user described using a scanner to monitor engine temperature and set the fan’s activation point. With a 195°F thermostat, the fan was set to activate at the same temperature. This process involved adjusting a trimpot, which controls the temperature threshold. The trimpot is sensitive, and fine-tuning was required to achieve the desired performance.
Once the fan activated, it ran at 60% power for about 30 seconds, reducing the engine temperature to 189°F. The user noted that the fan was powerful enough to achieve this drop quickly. The fan’s maximum power setting is 100%, which activates at 205°F. The soft start feature of the fan produced a noticeable noise, which the user could not determine if it came from the motor or the controller.
From a performance perspective, the user reported that the engine felt lighter and more responsive after the modification. The reduction in fan noise was also a significant benefit, as the previous mechanical fan was constantly audible. While the truck did not feel faster, the overall driving experience was improved due to the reduced drag and noise.
Additional Considerations and User Modifications
Some users reported issues with the fan activation timing when using ignition-switched power. In one case, the fans would not activate until the ignition was turned off, despite the engine remaining running. This resulted in only 4–5 volts at the ignition circuit, compared to the expected 12+ volts. A potential solution was suggested to be the addition of a diode to isolate the ignition circuit and prevent voltage drops.
For users with similar systems, such as those using Spal relays and Dewitts dual fan setups, the wiring configuration can vary. The user provided a step-by-step process to test the fans manually before integrating them with the ECM:
- Ensure 12 volts is supplied to the power wire and the ignition wire.
- Ground the control wire to activate the fan manually.
- Reconnect the ignition wire and test the fan with the key in the "on" position.
- Verify that the ECM can provide a ground when the temperature threshold is reached.
This process ensures that the electrical system is functioning properly and that the fan will activate as intended when the engine requires cooling.
Final Thoughts on Cost and Customization
The user emphasized that this project was both cost-effective and rewarding. While custom solutions would have been more precise, the budget-friendly approach using existing components worked well. The user also expressed interest in adding cabin control switches in the future, as the controller has provisions for both fan cut and fan start. However, they currently did not feel the need for such controls and were satisfied with the system's performance.
In terms of recommendations, the user highlighted the importance of using high-quality clamps and verifying the correct adapter size. They also encouraged users to measure their fan's current draw to ensure their electrical system can handle the load.
Conclusion
Electric cooling fan installation in vehicles such as the 2001 Ford F-150 and LS3 engines can be a rewarding project for DIY enthusiasts. By following the detailed steps outlined in this guide, users can achieve improved thermal management, reduced engine noise, and greater control over cooling performance. The use of components like the Mark VIII fan, American Volt adapter, and Flex-A-Lite controller provides a reliable and cost-effective solution. Careful attention to plumbing, wiring, and tuning is essential to ensure the system functions as intended. With the right tools and preparation, users can successfully complete this modification and enjoy the benefits of a modern, efficient cooling system.