Twin Electrical Fans

It’s been said that the factory fan consumes horsepower, and I’ve heard conflicting results as to what the power increase would be if you were to eliminate the fan and go electric. Me, I just don’t like the idea of that big thing swinging around on the end of the water pump, putting all that extra stress on it. It’s called a Water Pump, not a Fan Turny Thingy. Let’s let the water pump do it’s job and find another way to pull air through the radiator.


Overview of Project:

The factory fan puts moves around 6000 cfm at 3000 rpm, and you could buy a couple of 16″  Perma Cool fans (around $100 each) that, together, would make around 5900 cfm. But I ran my truck without a fan for almost 8 months and noticed very little change in running temps. The truck sure got hot sitting in traffic, though, so I started to think how to come up with a cheap solution. I raided the local salvage yard and bought 3 electric fans (one was a twin unit that I thought would work sweet) for $20. Turns out the twin unit had one motor that was so big it wouldn’t fit between the engine pullies and the radiator. So I pulled the other 2 fans (15″ and 14″ diameters) off their plastic frames and went to work.

Some basic fabrication skills are needed to weld up a frame sturdy enough to hold the fans while they’re turning, but it doesn’t have to be anything huge. I bought some pieces of square steel tubing from Home Depot, and a circuit breaker and relay from NAPA. Wiring is very basic, but was easier for me because I have eliminated my a/c. If you still run a/c you’ll need to have a relay that will turn the fans on when the a/c is turned on.  You can add a thermal switch, too, but I just wired mine to a dash switch and will use it only when I see the temps climbing.

Materials Used:
  • Salvage yard electric fans:  $20.
  • Misc. steel for fabricating the fan mount:  $15
  • Circuit breaker and relay:  $15
  • 12 ga. wire and misc. wiring materials I had on hand.
  • Total cost is around $50, and should work as well as the $250 fans.


The Fans:

Here’s a pic of the 3 fans. I couldn’t use the twin as a unit, so I used one from it and the other fan.

This is the frame I made. Shows the mounting tabs for the 2 fans and brackets that get bolted to the truck to hold them away from the radiator. Electric fans need to be very close to the radiator, like 1/2″ or so if you don’t have a shroud.

The fans mounted in the frame. The fans were then wired together, the wires covered in loom and terminated with a 2 prong weatherpack plug.

A bracket I made to hold the 20 amp circuit breaker and relay.

Some of the wiring needed. The one red wire goes to the battery, the plug goes to the fan plug. Not shown is the wire going to the dash switch that’s hooked to an ignition-key source to activate the relay.

Fans mounted. In the middle left of the pic you can see the breaker and relay.


These two fans move ALOT of air. You can definitely see the temp gauge drop with these suckers spinning. For the price they should do the trick, easily. I’ll have to monitor how well they work in the middle of summer once the ambient temperature starts to climb, but so far so good!

Happy wrenching.

This entry was posted in Cooling, Electrical and tagged . Bookmark the permalink. Both comments and trackbacks are currently closed.