Mounting Electric Fans: A Step-By-Step Guide For Your Radiator

Installing an electric fan on a radiator can be a complex process, and the steps may vary depending on the make and model of the car. The first step is to choose the right size of the electric fan for your engine. Once you have the fan, you will need to remove the existing fan from the water pump or crankshaft pulley and follow the fitting instructions to mount the new fan on the front or rear side of the radiator. You may need to assemble the fan to the mounting brackets and secure it to the radiator using special ties, washers, sponge pads, and nuts. The process also involves wiring the fan and connecting it to the car's electrical system. Finally, you can test the fan by reconnecting the battery and adjusting the thermal switch.

Choose the right fan for your engine size

When choosing the right fan for your engine, there are several factors to consider. Firstly, understand your airflow requirements in terms of volume and pressure. The fan size and positioning will depend on the engine envelope size and the location of other vital components. Consider how much space you have available and how fast you want the fan to spin, which will be based on your airflow requirements and operating conditions. Your fan supplier can help you determine the ideal fan speed. Additionally, fans can turn clockwise or counterclockwise, and they can either "blow" air towards the engine or "suck" air away from it, resulting in four different rotation-direction options.

Another important consideration is the location of the engine and any obstructions. If the engine or another obstruction is located directly downstream from the fan, this will impact the fan configuration. Operating temperature, altitude, and relative humidity are factors that affect air density and should be taken into account. Matching the right fan with the proper on/off, two-speed, or variable-speed fan drive will ensure optimal performance.

When it comes to electric radiator fans, you can choose between pusher and puller designs. Pusher-style fans are mounted on the front of the radiator and blow air through the radiator core. On the other hand, puller-style fans are mounted behind the radiator and draw air through the core. Puller-style fans are generally recommended when the electric fan is the primary cooling source. However, if you opt for a pusher-style fan as an auxiliary cooling source, ensure that it covers as much of the radiator core as possible.

To determine the optimum airflow, refer to the horsepower and airflow levels provided by aftermarket fan companies. Choose a fan that matches or exceeds your vehicle's power output or airflow requirements. As a general guideline, engines that are 5.0-liter (302 cubic inches) or larger should be paired with an electric fan with 2,800 or higher CFM (Cubic Feet per Minute). CFM indicates the amount of air the fan can move, and matching the CFM rating of the fan to the size of the engine is crucial for effective cooling.

Lastly, consider the benefits of using a single or dual fan setup. While two fans can provide better cooling than one, there are additional considerations such as mounting, shroud requirements, and wiring needs. Space constraints, charging system limitations, and the design of the radiator may influence your decision.

Prepare the radiator

To prepare the radiator for installing an electric fan, start by draining the cooling system and removing the top hose at the radiator end. You may also need to remove the generator drive belt and unbolt the existing fan from the water pump or crankshaft pulley. Refit the bolts to secure the pulley, ensuring they don't protrude too far to the rear. If needed, add extra washers under the bolt heads to compensate for the removed fan.

Check the fitting instructions to determine whether the new electric fan should be mounted on the front or rear side of the radiator. The fan may need to be offset to clear any obstructions, such as the water pump, and in some cases, you might need to remove the radiator temporarily to fit the fan.

If your radiator has a fan shroud, you can choose to remove it, as it won't significantly impact the performance of the electric fan. However, you can keep it if desired. Decide on a mounting method for the electric fan. You can use individual brackets to connect the fan to the mounting points of the shroud, or opt for zip-tie-style mounts, which are faster and more affordable.

Some electric fan kits come with the fan and motor already assembled to the mounting brackets, while others require assembly. If your kit requires assembly, attach the motor to the support brackets. You will also need to attach the thermal switch to its bracket near the radiator. If there are no existing screws or bolts, you may need to drill holes and use self-tapping screws. Ensure the sensor tube is straightened and inserted into the top hose, and place a rubber seal on the radiator hose stub.

Attach the fan to the radiator

The process of attaching an electric fan to a radiator depends on the size of the engine and the type of fan being installed. The Pacet electric cooling fan, for instance, comes in two sizes: a smaller fan that is ready assembled with the motor in its support bracket, and a larger fan that requires assembly using support brackets and a motor.

Before attaching the fan, ensure that the fitting instructions are followed to determine whether the fan should be fitted to the front or rear side of the radiator. In some cases, the radiator may need to be removed to fit the fan. Additionally, the fan may need to be offset to clear any obstructions, such as a water pump.

To attach the fan to the radiator, place the assembled fan against the radiator. Hold the fan in place and fit a fibre washer between one of the fan brackets and the radiator face. Next, fit a cone-shaped spring to a plastic mount, and pass it through the bracket, washer, and radiator fins. Repeat this process for the remaining brackets.

Fit fibre washers to the ends of all four plastic mounts protruding from the radiator, followed by the sponge pads. Secure each mount with a plastic 'nut', tightening it with an open-ended spanner while pulling the mount through the radiator with pliers.

For added stability, you can create a piece to go over the top of the fans, bolting them in place without putting any stress on the radiator core. You can also add rubber flaps or doors to the setup. This ensures that when the fan is inactive, air can still flow through the radiator, and when the fan is on, it pulls the air through more effectively.

Secure the fan with ties, washers, and nuts

To secure the fan to the radiator, you will need ties, washers, and nuts. Some kits come with the fan and motor already assembled with the mounting brackets, while others require you to put them together.

The Pacet electric cooling fan, for example, comes in two sizes, with the smaller fan arriving ready-assembled with the motor in its support bracket. The larger fan, however, requires assembly using support brackets and a motor. Both kits are supplied with thermal sensors, mounting brackets, and the necessary ties, washers, sponge pads, and nuts.

When securing the fan, place the assembled fan against the radiator. Hold it in place and fit a fibre washer between one of the fan brackets and the radiator face. Fit a cone-shaped spring to a plastic mount, then pass the mount through the bracket and washer, and then through the radiator fins. Repeat this process for the other brackets.

Fit fibre washers to the ends of all four plastic mounts where they stick out of the radiator, followed by the sponge pads. Fit a plastic securing 'nut' to the end of each mount. Tighten them by holding the 'nut' with an open-ended spanner while simultaneously pulling the mount through the radiator with pliers.

Connect the fan's wiring

To connect the fan's wiring, you must first attach the thermal switch to its bracket. Find a point near the radiator to mount the switch. If there is no existing screw or bolt, drill holes and use self-tapping screws to attach it. Ensure the sensor tube is free of sharp bends and cannot fall onto hot or moving parts.

Next, disconnect the battery. Run a wire from the live terminal on the fan motor to an ignition-controlled feed. Install an in-line fuse holder on this wire. Then, run the remaining wire from the motor to one of the thermal switch terminals. Connect the other thermal switch terminal to a nearby earth point.

Reconnect the battery, then turn the thermal switch adjusting screw fully clockwise. Start the engine and let it warm up until the temperature gauge reads just above normal. Slowly turn the adjusting screw anticlockwise until the fan starts. The fan should run for 20-30 seconds before cutting out.

Finally, drain the cooling system and remove the top hose at the radiator end. Straighten the end of the sensor tube and insert the sensor into the top hose. Place a special rubber seal on the radiator hose stub, then lay the straightened sensor tube on the seal.

Frequently asked questions