I used an OEM '94-'97 Tbird 2 speed fan.
I attached it to the OEM truck fan shroud to keep a good flow of air through the radiator. The Tbird uses a 130 amp alternator-the same alternator that the Navigator uses. Power gains are minimal, mileage gained was 1.5-2 mpg consistently. I've heard OF nothing but problems out of that flex-a-lite "kit". The fan controller that is included with that "kit" commonly fails.
JL

 

It is a procomp 16 inch fan with a thermostat that pokes into the radiator fins. Fan wasn't big enough I know I just went electric in the winter months to offset the worse gas mileage it was getting due to the cold.
Electric fans do help with gas mileage for sure.A close guess would be 1 mpg highway and 2 mpg around town

 

Thanks for the tip Johnny. the thunderbird fan looks great and the shroud is 18.5x22. I think that should cover most of the radiator. Oh yeah best part is you can by it for 59.99 on farnconversion.com. The relay is 17.99 with shiping this works out to right around 100$ project. I made a spreadsheet to caslculate the fuel savings. Assuming I get a 2mpg increase for 100$+elbow grease this project will pay for itself around 2500 miles down the road.

I was going to ask if there was a particular fan controler setup you perfered?
the last thing I need is to have this thing not work when my wife is driving it.

 

Anyone tried running camper shells or toneau covers to increase mileage?

 

That's why you had issues with the fan in warmer weather. Those aftermarket fans do not have enough motor power and a poor fan blade design to keep the small motors from burning up trying to turn them. The result is a weak airflow that does not cool efficiently.
OEM fans are built for 100K mile durability, have much better designed fan blades,and have larger motors that can move the air needed for cooling in even 100+ degree days.

I used a Derale brand adjustable fan controller.
Derale Cooling Products 16749 - Derale Performance Deluxe Adjustable Controllers with Pipe Threaded Probes - Overview - SummitRacing.com
One good thing is that you can wire this controller to fire up the fan when the A/C compressor is on for good cooling. This controller was wired to trigger a high current relay that can handle the amp draw of the Tbird fan. It WILL MELT the 30/40A cube type relays that they are showing on that fanconversion.com . DO NOT use one of those-it WILL fail, and leave you stranded.
This is the relay type you need:
BOSCH TYCO RELAY 75 AMP 12V HEAVY DUTY HIGH CURRENT | eBay

JL

 

I have used flex a lite befor and serveal others and found, well, their cfm ratings are, well.....crap.

The oem units (police crown vics, mark VIII, lat model Cougar V8) all are smaller, much more efficient than anything I have seen, tried in the aftermarket (performance) world. I recently had to relace the entire fan/schroud assembly in our 1997 cougar sport (V8), the oem replacement unit complet was $90 includng tax.

 

i had a tonneau but it didnt really do anything except on long highway trips (which i rarely do) so i just took it off a bought a tool box.

 

I'm going to hit victory auto wreckers. I Hate that whiring sound of a mechanical fan! Also throttle response has changed.

 

I'm getting about 11 mpg.

 

<a href="http://www.fuelly.com/driver/acfirecat6/f250-super-duty" target="_blank"><img src="http://www.fuelly.com/sig-us/50329.png" width="500" height="63" alt="Fuelly" title="Share and compare MPG at Fuelly" border="0"/></a>

 

Not a superduty but still a 5.4L. '05 F-150 5.4L 3V two-wheel drive ex-cab 6.5'bed, 3.55:1 gears, 30.25" tires, premium-tune, custom y-pipe, 3" single exhaust. 10.5 city and 16 mpg on a long interstate trip once. It generally falls between 10.5 and 13 mpg mixed driving.

 

I have an 03 5.4l with auto 102xxx and Im getting 11.5-12 all the time. Ihave an 8" BDS lift with 37x13.5x16..... I have 4.56yukons, k&n cold air, diablo tuner w/ custom tune. I just filled it up this morning and got 11.6 mpg so i cant really complain

 

Fellas,
03 SD tow pkg...reg cab 8' box.. 5.4L ..13K miles on Grooms crate motor..w/JBA headers..still on original exhaust...285/75-16's and 3.73's....
Drove to Nashville from PA and got 15.9 on the highway with no tailgate and mirrors folded in..Threw a Husaberg dirt bike in the back that I bought down there, folded the mirrors out, and put the pedal down a bit coming back...and got 17.1...uphill..
I don't get it !!! Must be the bike sticking up above the cab a little helped with the airflow or something...
.........................Clutch47................. .........................

 

Clutch: A couple of tankfulls better or worse really doesn't tell you much. Fuel economy needs to be measured over thousands of miles to be accurate. Still, averaging 16 give or take, like you did is pretty good.

 

Ok I just got my 05 F250 4x4 late last week and have only had a chance to run one tank through it, but for kind of around town driving I do here in southern Maryland this first tank was 14 MPG. My old 98 F150 4x4 was only getting me 16 MPG for the same type of driving (and it had the 4.2L V6 and 3.55 gears).

Truck details are 2005 F-250 Super Duty Crew Cab 4x4, 5.4L, 3.73 LS, Torqushift Auto, LT285/70-17 tires, ESOF transfer case. 51K when I got.

My old 87 F250 super cab with the 6.9L diesel has blown a combustion chamber (needing head work) after 300K+ miles and the condition of the body, trans and rear end just made it too expensive to fix (I have done all the work on this truck for the last 15+ years) even with me doing all but the machine shop work. It is just too rusty and too worn out finally. The 98 F-150 was my dads truck from new, but being it was from New England everything under the hood and body is a mass of rust. Working on it is (now was) an exercise in flustration with broken/rusted bolts etc .

So hopefully this 05 will be as good as my 87 was (I am really going to miss that truck), minus the fact it is not a diesel. Fuel mileage of this new truck sucks compared to the old diesel but is not bad compared to the F-150. That F-150 can really eat the gas when towing (it has only ever towed my utility trailer with my motorcycle on it, this is a faily light setup of less than 1500lbs) even at 60mph. I will provide an update once I get a chance to put some miles on it.