An electric "pusher" fan can help when the  mechanical one needs a blow

by Jimmy Nylund
 

Something needs to make air flow through the radiator in order to make it efficiently dissipate the heat drawn from the engine. In a regular car, the airflow created by going down the road usually does the trick, but just like a car struck in a traffic jam, a four wheeler on the trail doesn’t have the benefit of natural airflow through the cooling fins. Instead, mechanical means of forcing air past the coolant are needed.

Usually, this is accomplished with a belt-driven fan drawing air through the radiator. This means that when the engine speed is high, so is the fan’s speed, and then consequently also its efficiency. That’s great for racing up Pike’s Peak and other fast paced activities, but not necessarily the hot ticket for trails where engine rpm can remain quite low during the most challenging portion, sometimes for hours on end.

Left with the hot (but minus the ticket), one alternative is an electric fan, which doesn’t know (or care) what engine rpm, road speed, or power requirements on hand are, and simply turns on to cool the engine as needed. Often used as an

An M130 pusher fan measures 15 x 13.5 inches and is only 2.25 inches deep. With a 12-inch diameter fan turning 2,000 rpm, Flex-a-lite rates the M130 for cooling up to a 125hp engine (100 with air conditioning). That cooling capacity is in addition to stock when used as an auxiliary pusher. Bracketry is included for perimeter mounting, as well as hardware for through-the-core fastening. So are an adjustable thermostat, wiring, connectors, and fuse.

OEM complimentary, the electric fan can be made to turn on when a sensor tells it the belt-driven fan can’t keep the temperature in check by itself anymore. An electric fan can also be manually switched on and off by the driver as engine temperature warrants, and it’s also frequently used alone, with no aid from a belt-driven fan. Either way, an electric fan can be a "pusher" (mounted ahead of the radiator) or a "puller" (mounted between the radiator and engine). Puller fans are generally about 10-percent more efficient than pushers, and mostly used in lieu of a belt-driven unit, while a pusher is often easily added to an existing setup, ready and able to help when the going gets rough.

Custom brackets or the included through-core hardware can be used on vertical-flow radiators. Here, a plastic "bolt" is pushed through the fins, between the tubes. Note the hex head that fits in the hump on the shroud, keeping the bolt in place and from turning. In this particular application, the shroud can rest on the lower tank, so the through-core mounting method puts very little stress on the core.

If possible, mount the shroud to the radiator’s frame, using the supplied brackets (or make them yourself). That should work on most cross flow units. Also, the preferred method of installation is with the radiator in place, after removing grill if necessary; this radiator was already out, which made it easier to take the photos.

Mount the control box within 16 inches or so of the upper radiator hose neck in order for the temperature sensor’s capillary tube to reach --- or on the shroud, if the leads for the fan motor are to be plugged in directly, This positioning on the grille was ideal for the temp sensor, and as high as possible to keep water from getting into the box

At the engine side (on a pusher fan), a rubber "washer," a stiff plastic washer, and a wing nut are used to secure the "bolt." This setup is removable and reusable, unlike the tie-wrap-action fasteners of past.

The temperature-control sensor goes in the upper radiator hose, and the small gasket (on the radiator neck) allows the capillary tube to fit, yet get a good seal. Flex-a-lite has explicit instructions on how to make this step correctly, and they’re worth heeding to avoid potential leakage or damage to the tube.

Adjust the fan to come on at the desires temperature, between 180 and 240 degrees, is done on the control box (here shown separately--- ours’ was installed upside down and isn’t very visible). These puller and pusher fans are available from Flex-a-lite in various sizes, including units to specifically fit Wranglers S-10s, Toyota pickups, and Ranger/Bronco IIs.

Simple wiring (positive, negative, and fan motor connections) makes the Flex-a-lite come on as needed. It can be wired to run for as long as the temp sensor dictates, or to go off with the ignition. Optional circuits include tying into the air conditioner wiring (the fan comes on with the A/C), and a switch fro turning the fan on at will.