I finally got around to replacing the stock clutch fan with a Zirgo electric fan. I used a Zirgo 16" 3300 cfm fan, and adjustable thermostat.
This mod took longer than I thought it would, but it was still way worth it. Now the engine doesn't ROAR to life like it used to. It starts up nice and easy. It's really amazing how quiet the engine is now. I can almost here crickets chirping in the background.
The engine also seems to have more pep. I don't have any dyno numbers, but I'm pretty sure that the engine accelerates and "winds up" faster.
It also warms up quicker, which is nice on a cold night like tonight. It only takes a few minutes of driving to get it up to normal temp. I drove a few miles before the fan came on. I have it set to come on at 195 degrees F. When the fan turns ON it's not that loud. It's certainly quieter than the stock fan, but still audible from the cab.
And if for some reason I need to go through deep water or mud then all I have to do is open the hood and turn the thermostat up to 240 degrees, and the fan will shut off; then I don't have to worry about water or mud tearing up the fan.
Now for the install details:
I removed the grille so I could get a little closer to the engine for reaching down in there. And for mounting the thermostat control.
Take off the engine cover.
Take off the 8 plastic pins that hold the trim piece on top of the radiator and core support. Pop up the center part of the pin with a flat head screw driver.
Pull off the little hose on the reservoir.
To get them out you have to remove the fan and the shroud at the same time. I used a ratcheting wrench to take off the 4 nuts that hold the fan on. I took off two nuts and then started the engine for a second so that the other nuts would spin around to the passenger side of the engine, where they are easier to reach. Just let the fan sit there. Then take out the two bolts that hold the shroud at the top corners. That is all that holds the shroud. The bottom part of the shroud fits into clips on each side. Just pull straight up, and bring the fan up with the shroud at the same time. There is a little nub at the bottom of the shroud that gets hung up on the bottom radator hose. Get under the front of the truck and squeeze the hose and then push up on the shroud. Now it should all come out with a little manuvering and some sweet talkin'.
Put the 4 nuts back on the pulley. The bolt studs aren't threaded all the way because of the mounting flange of the fan/clutch. So you now need to use a washer on each stud to work like a spacer. I then put red Loc-tite on the threads and tightened down the nuts.
To make the fan as efficient as possible you need to seal off any space on the sides of the fan, so that the fan can only pull air straight through the radiator. To fill in this gap I made a "donut" out of a sheet of aluminum. I used an air-shear, but tin snips should work too. I then screwed the fan to the aluminum with 8 screws. Then I bent the aluminum to fit the curves of the inside of the stock shroud. Then used Pop-rivets around the circumference to hold the aluminum to the shroud. It turned out to be pretty solid.
(For rivets that don't tighten down real well, you can place a hammer on the back side of the rivet and then hit the other side with another hammer. This will smash the rivet and make it tighten up on the metal. Stainless steel rivets will anchor down better than aluminum rivets, but they are much harder to use with a pop-rivet tool.)
Then I sealed up the circumference with some silicone to make it more secure and air tight where the aluminum and the shroud meet.
I mounted the thermostat control on the front side of part of the core support, next to the passenger-side headlight. I used an existing hole for the knob to stick through into the engine compartment. The thermostat sensor goes inside the radiator hose. I opened the petcock on the bottom drivers side and drained out a little fluid so that it wouldn't spill all over when I took off the top radiator hose. Put the sensor in, clamped it back down, filled the radiator back up with fluid. You could use a small bucket to catch the fluid underneath, and then pour it back in the top once you are ready. There is a hole in the skid plate right where the fluid drains out of the petcock. It isn't messy at all,
Then I did the wiring. I used a relay, which is connected to the ignition circuit, so that the fan will shut off whenever the engine is off. Otherwise the fan will keep running until the engine is cooled below 180 degrees; which is just a waste of battery power. Then I ran a 12 gauge power wire from the output of the relay to the positive of the fan and then the negative wire runs to the thermostat. These fans can blow either way, depending on how you have the polarity going to the fan. Be sure that the fan is blowing toward the engine, which sucks air through the radiator. This is called a pulling setup. Pulling air cools the radiator better than a pushing setup, where the fan is in front of the radiator.
Here it is all put back together.
I would certainly recommend this mod to anyone that can tackle it. I expect to get better MPG, a few more HP, and better cooling on hot days and in traffic. Oh, and the faster warm-up, and quieter engine is nice too.
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