Installing a Derale Electric Fan Conversion: Cost Breakdown and Performance Benefits

A vehicle’s cooling system is a critical component that directly affects engine longevity, performance, and fuel economy. Traditional mechanical fans, while reliable, draw power directly from the engine crankshaft, creating parasitic drag that saps horsepower and increases fuel consumption. Derale electric fan conversions offer a modern alternative, replacing the belt-driven fan with a thermostatically controlled electric unit that runs only when needed. This upgrade is particularly popular among enthusiasts looking to free up engine power, improve cooling in stop-and-go traffic, and reduce noise. However, before diving into the installation, it’s essential to understand the total cost, the performance gains, and the practical steps involved. This article provides a comprehensive breakdown of the expenses, the measurable benefits, and a detailed guide to completing the conversion yourself.

Understanding Derale Electric Fan Conversions

Derale is a well-known brand in the automotive aftermarket cooling industry, offering a wide range of electric fan kits designed for everything from classic muscle cars to modern trucks and off-road rigs. Their electric fan conversions replace the factory mechanical fan – often paired with a clutch – with a slim-profile electric fan that mounts directly to the radiator or a custom shroud. The core advantage is that electric fans are not driven by the engine belt; instead, they draw power from the vehicle’s electrical system, typically triggered by a temperature sensor or an adjustable thermostat controller.

By eliminating the mechanical fan, the engine no longer has to spin a heavy metal fan blade constantly, which reduces rotational inertia and allows the engine to rev more freely. This reduction in load translates to a measurable increase in rear-wheel horsepower – typically 5–15 hp depending on the engine size and fan design. Additionally, electric fans only operate when the engine reaches a preset temperature, meaning less noise and less aerodynamic drag when the fan is off. Derale offers several product lines, including high-performance dual fan setups, PWM-controlled fans for variable speed, and universal fit fans for custom applications. Each kit comes with necessary mounting hardware, wiring harnesses, and detailed instructions, though some may require additional components like a relay or secondary temperature switch.

Cost Breakdown of a Derale Electric Fan Conversion

The total cost of a Derale electric fan conversion varies widely based on the vehicle, the fan kit chosen, and whether you perform the labor yourself. Below is a detailed breakdown of every major expense category, including options that may lower or raise the final total.

Fan Kit Cost: $150 – $300

The fan kit itself is the largest expense. Derale’s basic single-fan kits start around $150 for models designed for smaller radiators or moderate cooling needs. High-performance dual fan kits with larger airflow ratings (e.g., 2,500+ CFM) can cost up to $300 or more. Some kits come with a pre-mounted shroud, while others require you to attach the fan to an existing shroud or custom setup. For vehicles with tight engine bays, consider Derale’s “slim” series fans that measure less than 3 inches thick, which may cost slightly more but offer easier fitment.

Wiring and Connectors: $20 – $50

Most Derale kits include a basic wiring harness with fuses and relays, but you may need additional wiring supplies depending on your installation. High-quality automotive wire (12–14 gauge), heat shrink connectors, a fuse holder, and a relay socket are common additions. If your kit does not include a pre-installed relay, budget $10–$20 for a standard 30–40 amp relay and socket. For installations requiring a secondary temperature control, you may also need a wiring harness extension or additional connectors.

Thermostat Control and Sensors: $30 – $80

Derale offers several temperature control options. A simple adjustable thermostat controller that screws into the radiator fins or a radiator hose costs between $30 and $50. More advanced PWM (pulse-width modulation) controllers that allow variable fan speed based on temperature can run $60 to $80. Some enthusiasts prefer to use a dedicated temperature sender in the intake manifold or cylinder head, which adds the cost of a threaded adapter and splice. If you already have an aftermarket EFI system that controls the fan, you may skip this expense entirely.

Mounting Hardware and Custom Shroud: $0 – $100

While most Derale kits include universal mounting brackets and zip ties, a secure installation often requires additional hardware. You may need aluminum L-brackets, rubber isolators, stainless steel screws, or a custom-fabricated shroud for non-standard radiators. Prices range from $10 for basic hardware to $100 for a custom laser-cut shroud ordered online. For many vehicles, the included mounting straps are sufficient, but for off-road or high-vibration applications, investing in metal brackets is wise.

Labor Costs: $0 – $200

If you choose to have a professional mechanic install the conversion, labor rates typically range from $100 to $200, depending on the shop’s hourly rate and the complexity of the vehicle. Installing a fan conversion is a 2–3 hour job for a skilled technician. DIY installation saves this cost, but requires basic mechanical and electrical skills. If you do the work yourself, you will also need to set aside a few hours for the job.

Total Estimated Cost: $300 – $600

Summing all the potential expenses, a complete Derale electric fan conversion typically falls between $300 and $600. The lower end represents a DIY installation using a basic single-fan kit with minimal additional wiring. The higher end includes a premium dual-fan kit with a PWM controller and professional labor. For most vehicle owners, the investment pays for itself over time through better fuel economy and reduced maintenance.

Performance Benefits of Derale Electric Fans

Switching from a mechanical fan to a Derale electric fan isn’t just about saving weight; it offers tangible performance improvements that can be felt and measured. Below are the key benefits, supported by real-world data and common owner experiences.

Improved Cooling Efficiency

Electric fans provide targeted airflow exactly when and where it’s needed. Unlike mechanical fans that spin at a fixed ratio relative to engine RPM, electric fans can be controlled by a thermostat to turn on at a precise coolant temperature – typically around 180–200°F. In stop-and-go traffic or off-road crawling, where engine speed is low and heat builds rapidly, the electric fan runs at full speed, pulling air through the radiator much more effectively than a slowly spinning mechanical fan. Many Derale dual fan setups exceed 3,000 CFM total airflow, which is more than sufficient for high-performance engines or vehicles with heavy aftermarket air conditioning condensers and transmission coolers.

Increased Horsepower and Torque

One of the most frequently cited benefits of electric fan conversions is a gain in horsepower. A typical mechanical fan assembly can absorb 5–15 horsepower at high RPM due to its mass and aerodynamic drag. By removing that load from the engine, those lost horsepower are transferred to the wheels. On a chassis dynamometer, many vehicles see a 5–10 hp increase at the rear wheels after the conversion. While the gains are modest, they are consistent and noticeable – especially in vehicles with smaller engines or those already close to maximum output. For driver-focused cars, the improved throttle response from eliminating the viscous fan clutch is a welcome improvement.

Better Fuel Economy

Reducing parasitic drag on the engine directly improves fuel efficiency. Although the alternator must work slightly harder to power the electric fan, the net effect is often a 1–3% increase in highway fuel economy and a 2–5% improvement in city driving. The fan only runs when needed, so during most highway driving the fan is off, further reducing electrical load. Over the course of a year, the savings can partially offset the initial installation cost. For daily drivers, this benefit alone makes the conversion worthwhile.

Quieter Operation

Mechanical fans, especially those with solid clutches or fixed blades, produce a constant roar that can be heard inside the cabin. Electric fans operate at a much lower noise level, particularly when running at partial speed. Most Derale fans are designed with aerodynamically optimized blades that minimize turbulence. When the fan is off (which is most of the time on the highway), the engine bay is nearly silent, reducing driver fatigue on long trips.

Customizable Cooling Control

Derale offers several controllers that let you adjust the fan on/off temperature, and in some cases, vary the fan speed in proportion to coolant temperature. This allows fine-tuning for different climates, driving conditions, or engine setups. For example, a high-compression engine may require a lower activation temperature, while a turbocharged engine may benefit from a post-shutdown fan run timer. With the right controller, you can also wire the fan to a manual override switch for temporary full cooling during hard track sessions.

Reduced Engine Wear and Belt Maintenance

Removing the mechanical fan reduces the rotational mass on the water pump and eliminates the risk of a fan blade explosion due to fatigue. It also means one less accessory on the serpentine belt, which decreases belt wear and can extend the life of the water pump bearings. For vehicles with tight engine bays, the extra clearance often makes access to other components easier.

Installation Process: Step-by-Step Guide

Installing a Derale electric fan conversion is a project that most DIYers can complete in an afternoon with basic tools. The process involves removing the old fan and shroud, mounting the electric fan, wiring it to a relay and thermostat, and testing the system. The following steps assume you have a universal Derale fan kit and moderate mechanical ability. Always consult your specific kit’s instructions for torque specs and wiring diagrams.

Tools and Materials Needed

  • Socket set and wrenches (metric and SAE)
  • Screwdrivers (Phillips and flathead)
  • Wire strippers, crimpers, and heat shrink
  • Multimeter (for testing circuits)
  • Drill with metal bits (if mounting brackets require new holes)
  • Zip ties and wire loom
  • Dielectric grease for electrical connections
  • Safety glasses and gloves

Step 1: Disconnect Battery and Drain Coolant (If Necessary)

Safety first – disconnect the negative battery terminal to prevent accidental shorts or fan activation. If your vehicle has a mechanical fan that uses a clutch mounted directly to the water pump, you may not need to drain coolant. However, if you are also replacing the radiator or removing the shroud that surrounds the radiator, it’s best to drain enough coolant to lower the level below the hose connections. Typically, you only need to drain a quart or two to remove the upper hose for shroud access.

Step 2: Remove the Mechanical Fan and Shroud

Loosen the mechanical fan’s retaining bolts or clutch nut. Most mechanical fans require a special wrench or a large crescent wrench to hold the pulley while turning the nut counterclockwise. After removing the fan, remove the factory fan shroud by unbolting it from the radiator support. Some shrouds are also attached to the bottom of the radiator; work carefully to avoid damaging the cooling fins. With the shroud free, you now have clear access to the radiator surface.

Step 3: Mount the Derale Electric Fan

Derale fans typically mount using long zip ties that pass through the radiator core fins. While this is quick, for a more secure installation, use the included metal brackets that attach to the radiator support or shroud. For universal kits, you may need to drill holes in the radiator support and attach brackets. Position the fan so it covers the maximum surface area of the radiator. If using zip ties, make sure they are tight but not so tight that they warp the radiator fins. For dual fan setups, mount both fans symmetrically and ensure they do not interfere with each other or with accessory belts.

Step 4: Install the Temperature Controller

Derale’s standard temperature controller includes a probe that slides between the radiator fins. Insert the probe into the radiator core at a location where it will measure hot water entering the top of the radiator. Secure the probe with the included rubber grommet or zip tie. Alternatively, you can install a threaded temperature sender in the radiator hose (using a hose adapter) or in the intake manifold if you prefer a more accurate reading. Connect the controller’s wires according to the diagram: typically, a battery positive, a ground, and a switched positive for the fan relay.

Step 5: Wire the Fan and Relay

The fan should be powered through a high-current relay controlled by the temperature controller. Direct wiring without a relay can overload the controller. Use a 30–40 amp relay and a 30 amp inline fuse. Route the power cable from the battery positive (through the fuse) to the relay’s contact terminal. The relay’s output goes to the fan positive terminal. The fan negative connects to chassis ground. The relay’s coil is triggered by the temperature controller’s output. Most Derale kits include a harness with these components pre-wired – you just need to connect the power and ground. For safety, wrap all connections with heat shrink and use wire loom where the wire passes near hot or sharp edges.

Step 6: Test the System

Reconnect the battery and start the engine. Let it idle and observe the temperature gauge. The fan should kick on when the coolant temperature reaches the preset threshold (usually around 190°F). If the fan does not activate, check the fuse, relay, and wiring connections. Use a multimeter to verify power at the fan and trigger signal from the controller. You can also test the fan by briefly jumping the relay coil to bypass the controller. Once the fan operates normally, shut off the engine and check for any loose wiring or potential chafing points. Adjust the thermostat setting if desired – lower for high-performance engines, higher for winter driving to reduce overcooling.

Common Pitfalls and Troubleshooting

Even with careful installation, a few issues may arise. The most common is inadequate fan coverage – if the electric fan is significantly smaller than the radiator core, hot spots can develop. In that case, upgrade to a dual fan setup or a larger single fan. Another frequent problem is fan cycling too often due to the probe not being inserted deeply enough into the radiator core. Push the probe further in so it contacts the coolant flow. Electrical issues often stem from poor ground connections; always sand the chassis mounting point to bare metal and use a star washer.

Long-Term Maintenance and Expected Lifespan

Derale electric fans are built with sealed ball bearings and are designed for long service life. With proper wiring (no excessive voltage drop) and clean connections, the fan motor should last 5–10 years. The only routine maintenance is to periodically check the mounting hardware for tightness and inspect the wiring for corrosion or abrasion. The temperature controller may fail over time, but replacements are inexpensive. Compared to mechanical fans that require periodic clutch replacement and bearing service, the electric fan conversion is largely maintenance-free.

Final Verdict: Is It Worth the Investment?

Installing a Derale electric fan conversion is a well-proven upgrade that delivers real benefits – improved cooling at low speeds, increased horsepower, better fuel economy, and reduced noise. The cost, ranging from $300 to $600 for a DIY installation, is reasonable considering the performance gains and long-term savings. For owners of older vehicles with inefficient mechanical fans, the conversion is a no-brainer. Even newer vehicles with electric fans can benefit from Derale’s high-flow dual fan setups as an upgrade over factory units. When you factor in the satisfaction of a cooler-running engine and the extra horsepower at your right foot, the project is well worth the effort.

For more information on specific fan models and compatibility, visit Derale’s official website. For additional guidance on wiring thermostatic fan controllers, refer to this comprehensive wiring guide and for owner experiences and installation photos, check out this popular hot rodding forum thread.