Install an Electric Fan for Increased Power and Cooling
Front wheel drive cars use an electric fan because the front of the motor faces the passenger side wheel well. But, our favorite cars, those with rear wheel drive, usually have a mechanical fan that is powered by the accessory belt system (or the serpentine belt in newer cars). This works fine, but, it robs you of usable horsepower and isn’t very efficient. Installing an electric fan frees up, on average, about eleven horsepower. This is horsepower that can then be put to use chewing up the pavement. It sounds difficult, but with a little help and some tools, it can be done in just a little over an hour.
Most of these instructions are based on Flex-a-Lite Electric Fan Kits. Other kits will be very similar in installation processes. Most kits come with a controller module, the wiring for which will be addressed in Part 2, How to Wire Your Electric Fan Controller.
Tools You’ll Need
- Measuring tape
- Wrench set
- Socket set and ratchet
- Flat-head and Phillips screwdrivers
- Pliers
- Multimeter
- Test light
- Crimp tool
- Cordless drill with Phillips screw tip
- 2 x 1/4 inch self-tapping screws
- 1/4 inch drill bit
- 1/4 inch rubber grommet
Measure for the Correct-Sized Fan and Clearance
You need to measure the radiator and the backspacing between the radiator and the water pump pulley so that you can purchase the correct electric fan kit. Too wide, and it won’t fit the radiator. Not wide enough and it won’t pull enough air through the radiator, causing the engine to run too hot. And, if you get one that’s too deep, you won’t be able to mount it because the water pump pulley will hit it. Refer to the photos below to make your measurements and then find an electric fan that covers 70% of the surface area of your radiator.
- Measure the width (A) and height (B) of the cooling core of the radiator.
- Measure the distance (C) from the radiator core to the water pump pulley. Subtract 3/4-inch from this dimension to account for pulley bolts and engine/chassis movement with the engine running.
Installing the New Electric Fan and Controller
1. Remove the Old Shroud and Fan
The first step in installing a new electric fan is to remove the old shroud. This is a relatively easy process.
- On some vehicles (like newer Mustangs) the radiator overflow bottle is mounted to the fan shroud, and will have to be removed first. Some are bolted in place, some just slide into place.
- Using a wrench and socket with a ratchet, remove the nuts and bolts securing the overflow bottle to the fan shroud and set it aside.
- The old fan shroud is normally going to be held in place by four bolts, two on each side, IF some of them haven’t been lost yet.
- Slide the shroud over the fan and let it hang.
- Using a wrench or socket and ratchet (usually 1/2 inch or 13 mm), remove the four bolts securing the fan/clutch to the water pump pulley by turning the bolts counterclockwise. If the pulley turns, push down firmly on the accessory belt to provide more tension.
- Remove the old fan and shroud and set them aside.
- Install the water pump pulley bolts that should have come with your new fan kit. They are significantly shorter than the old ones.
2. Mount the New Brackets to the Shroud
This is for the above-mentioned kit. Many kits come with adjustable brackets to give your new electric fan the best fitment possible. Depending on your application you’ll often receive a new top and bottom bracket while other times you’ll receive four – one for each side. Still, your particular electric fan may not have these brackets and instead their shrouds mount to the radiator with friction rods and push nuts. If you don’t have brackets, skip ahead to the next step.
- When mounting your brackets, tighten the top bracket more fully as an anchor but leave the others a little loose so you can fine tune the fitment later on.
- Put the shroud aside for now.
3. Mount the Control Unit
The control unit needs to be within 18-inches of the radiator hose feeding the radiator (usually the upper hose) because the lead for the thermal probe is only that long. It can be mounted on the fan shroud or the body/chassis, whichever is easiest. Once you’ve decided on a location, mount the controller using the two 1/4-inch long self-tapping screws (or the attachment method that comes with your kit). Hold the controller in place, place one screw into the Phillips bit on the cordless drill and tighten it into place. Do the same for the other screw.
4. Mount the Electric Fan and Prep the Shroud for Wiring
With almost all kits, you’ll find that the power wires for the fan need to be extended so they reach the controller (covered in Part 2), and the shroud needs a hole for the wires to be fed through.
- Based on where you decided to mount the controller, look for a good place on the fan shroud to drill a 1/4″ hole where the wires will exit the fan motor. Insert a grommet in this hole (if provided) and route the fan motor power wires out of the shroud through the hole.
- Mount the fan assembly and tighten the brackets, ensuring the rubber side gasket is compressed approximately 50% and the fan is centered on the radiator.
- Next, mount the radiator overflow bottle to the fan shroud bracket using the supplied bolts and large washers.
With the fan and controller successfully installed, we are now ready to get everything wired up! There are few wiring options to consider depending on application and how you intend to use your fan and we cover all this in Part 2, How to Wire Your Electric Fan Controller.
Photo credit: Bill Wrigley – Wikimedia CC & Flex-a-Lite
About the Author
Gearhead Diva Purveyor of the illest car stuff on the net, decreaser of stance and performance suck world-wide, proud superfan of mods and now recommended by 4 out of 5 people that recommend things.
