The car is a '92 5.0 with underdrive pulleys, a 3-row replacement radiator and a PA Performance 130 amp alternator upgrade. The stock fan was not keeping the car cool in stop/go traffic with the A/C on even with a fresh radiator and a 180 degree thermostat.
So I dug around the search function for quite some time figuring out what my options were. With some good help from “macx” and “blk91gt” through PM's, I set about installing a fan from an early 90's 3.8 Taurus, controlled by Flex-A-Lite's new high-capacity variable-speed controller (VSC)...part number 33054, $95 or so at Summit Racing
This VSC has a “soft-start” feature so it doesn't spike the charging system on startup. It has a 6-second delayed start after engine startup so it doesn't unnecessarily load during starting. It uses an included probe to measure radiator temp and starts the fan at 60% speed at that temp, raising it to 100% speed over the next 10 degrees. It has input for manual-on and manual-off switches, as well as input to turn the fan on any time the A/C compressor is energized.
I got a used fan from the Corral Classifieds and started mocking up its location. Many people mount it right side up and either move the factory overflow bottle to the passenger side with standoffs or use an aftermarket overflow bottle located near where the stock one was. Since my battery is in the stock location and I didn't want to screw around with relocating the stocker, I simply mounted the fan upside down and fastened the overflow close to its stock location, right on the Taurus fan. To do this, I used a dremel to cut holes in the fan shroud and transferred the factory spring clip-nuts from the mustang shroud to the Taurus shroud.
The fan fits nicely upside down into the factory clips in the radiator if you trim it to fit any reinforcements in the rad, like so. Please note that it's not in its mounted position, I just wanted to show the notch I ground in the shroud:
I originally had the VSC mounted on top of the fan's shroud, but I later moved it over to the airbox cover to keep it more isolated from vibration and heat.
The fan clips nicely at the bottom but needs to be secured a the top. I originally used plastic zip-type retainers designed specifically for this purpose, but the assembly just wasn't stable enough for my liking, so I fabbed up some top mounts out of something I found at random in a hardware store.
Even bolted to the shroud in 2 places, the overflow wasn't rock-solid like I needed it to be. The bottom of the overlflow no longer clips into anything to secure it. So I dug into my handy-dandy bin of leftover factory fasteners and used two self-tapping screws in two existing holes in the lower rad support to strap the overflow down across its existing tabs. It isn't pretty, but it's very effective..and hidden anyway.
The most time-consuming part was wiring it all together, mostly because I took a lot of time to figure out my routing, add in disconnects to some of the hard lines for ease of future removal, properly heat-shrink all the connections, etc. I probably spent $35 or so on wiring and supplies including a 40A Mega-fuse holder and fuse.
I also carefully applied heat-shrink, unshrunk at one end, to make “boots” for the spade connectors I was installing
I installed a 40-amp blade style Mega fuse and a water-tight fuseholder. Lots of smaller fuseholders are rated for 35 amps or more, but none do the medium or small sized blade fuses are, themselves. So I used the Mega fuse and stuck it over by the factory airbox.
I took advantage of the A/C auto-on function by tying a feed into one of the A/C actuation wires as they route from the engine to the drivers side fender. I found out it does indeed matter which one you use, so use a voltmeter with the engine running and the A/C switch “on” to find out which one is the higher-voltage one to use. Then this line gets plugged into port 7 of the VSC.
To provide ignition-switched power to the VSC, I tied into the power line for the Coolant Level Sensor, which you can see on the right of this photo. I tied the fan's ground to a ground bolt next to the battery, and tied the fan's positive line to the positive battery post.
The fan's wiring is Solid Black, Black w/Green Stripe, and Tan. The solid black is neg/ground and the Black/green is the high-speed wire which I'm using with this install. Tan low-speed wire left unattached.
I took the time to use corrugated plastic loom to protect the wires and provide a clean factory look.
What you can't see is the tie to the A/C feed wire because it's hidden behind the power steering reservoir. You also can't see the supplied temperature probe but it's just below and beside the upper rad inlet.
So here it is all mounted and wired. I used a piece of sheet aluminum I had laying around to make a block-off plate for the big notch in the shroud, and I purposely mounted the unit as far to the passenger side as possible, so I could have the most possible area of the radiator unshrouded. This aids with high-speed airflow and cooling. Doing this required trimming the shroud to clear the end tank on the radiator, which I insulated against wear with some foam insulation, but I don't have pics of those mods, sorry.
There's some more installation on the Flex-A-Lite site here, although this shows the cheaper, lower-amp unit: http://www.flex-a-lite.com/auto/html/vsc.html
It looks like a great success. So far, the car appears to cool down
with the A/C on instead of heating up. I'm sure it freed up a couple HP and it took a couple pounds off while cleaning up the engine bay.
Not counting the alternator upgrade, the fan upgrade cost me about $210 total for the fan, controller, wiring, fuse, insulation and looms, plus priceless little bits and pieces of fasteners and connectors I had sitting around.