2002 Thunderbird Hydraulic Cooling Fan Conversion

I'm looking to get rid of the Hydraulic cooling Fan on my Bird. I'm replacing the Radiator, and would like to also be done with the current fan cooling system. Does anyone have a good suggestion for Electric replacement fan kits for this model of T-Bird? Is there any conversion temp sensor that I need to incorporate as well?
I'm looking to get rid of the Hydraulic cooling Fan on my Bird. I'm replacing the Radiator, and would like to also be done with the current fan cooling system. Does anyone have a good suggestion for Electric replacement fan kits for this model of T-Bird? Is there any conversion temp sensor that I need to incorporate as well?
I would also be interested in a electric fan and get rid of the hydraulic cooling fan?

Gus Gutz

Well-Known Member
I know there is some sort of control device that tells the fan to spin up. The PCM tells that device to spin up the fan. I have no idea where that is but my Ford dealer replaced that two years ago when I kept overheating. I'm sure there would have to be some sort of connection to that device in your replacement
was able to install the new 16" electric fan inside the shroud, so everything like the A/C dryer bottle, etc bolted back up to the shroud-like factory fit. I made my own bracket out of thick aluminum to mount the fan speed controller. Wired from the nearby fuse box, a constant 12V, a switched 12V and from the A/C compressor relay, a signal wire to trigger the fan on high speed. After fine-tuning everything, the fan starts at 208 degrees and cuts out at 196. When A/C is on,, the fan stays on high speed. Here are a few pics of my work.
If anyone is looking to do this mod, I would be happy to share my info. I feel this is more of a reliable system than the original hydraulic system.
fan-converted.jpg fan2.jpg fan1.jpg hydraulic-fan.jpg
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Need to remove everything pertaining to the hydraulic cooling fan, pump, reservoir, lines, expansion tank. Install a 100’’ sepentin fan belt, install a flex a lite 3400 cam 15´’ fan and shroud assembly, install a flex a lite fan speed control #31165 , and fine tune adjustments... I check my engine block temperature with OBDII reader, stays 208 degrees with a/c on, a hot day.
I also have a 2002, and is the only year with this hydraulic system. I just finished swapping everything out to an electric fan system. The '03-'05 had the swap already done from the factory. First, you need to determine if your problem is from the hydraulic side,, or the coolant side. The first test, start the engine, leave it run a few minutes. Visually, your radiator fan should be spinning slowly. As the engine warms up, the fan should speed up. When you turn on the a/c, the fan should spin at its maximum speed. If all these procedures work, skip to the coolant side., if not, you will need to fix the issues. The fan speed is controlled by a small valve called the actuator. It is screwed into the hydrolic pump. It has a wire hooked up to it. It is not voltage, but a pulse. This system is not my favorite system and is why after screwing around to get it working, I gave in, and ripped it out and did the conversion. You can do a search on this site for my messages, and get an idea of the extent of work to do this.

if your problem is on the coolant side, first start with the degas bottle. Its the cap and plastic white bottle with coolant overflow. They often crack and fail.
if your thermostat is original, replace it with a factory one. there is a small purge valve by the degas bottle. Just open the screw and close it when the coolant leaks out. Don't forget, only use the gold dealer coolant ( a red container) nothing else. Don't mix with prestone, it will eventually turn to gel in the hoses.
monitor the level ( between the lines) of the coolant in the degas bottle.
There are some videos on youtube where people have done this to the lincoln ls which is the same platform build as the thunderbird.
I've looked around for these videos and can't find them. Anyone have any ideas? I have the parts to do the job, just need some insight on how the radiator will come out. I'm almost there, but it seems I'm going to have to remove the A/C lines on the front radiator, and I'd rather not if at all possible.


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Staff member
Found this online-
This is a write up on how to convert your factory hydraulic cooling fan to an electric cooling fan saving you a lot of money. I have done this conversion on 4 Lincoln LS's including 2 of my own. This should be the same process as the 2002 Birds.

I didn’t take step-by-step pictures but here's the info as I remember. You will need to purchase a Flex-a-Lite 183 cooling fan and a 99" or 100" x 13/16" multi rib v-belt. Removing the hydraulic pump is a pain so don’t say you weren’t warned.

Fan Removal
1. Remove intake tube and MAF housing
2. Remove radiator shroud/cover
3. Remove upper radiator hose and lower radiator hose (good time to replace thermostat, DCCV, coolant reservoir, etc at this time since you will need to bleed the cooling system after)
4. Unbolt the silver AC canister from the fan shroud and zip tie out of the way
5. Unbolt the aux heater pump from the fan shroud and remove the electrical connector.
6. Unbolt or cut the lines going to the hydraulic unit on the fan. These will be full of fluid so drain them into an oil pan and cut the hoses going to and from the cooling coil leaving an inch or two so you can plug them with a 3/8” bolt.
7. Unbolt and remove the fan shroud. I believe there are 2 bolts towards the top of the shroud and 2 bolts about halfway down, it’s tough to pull the shroud up and out of the engine compartment because the brackets on the bottom are big. Take your time and don’t put a hole in the radiator.

Hydraulic Pump Removal

1. Jack up the passenger side front of the car and support with jack stands.
2. Remove the alternator. 1 wire harness, the battery wire, and 3 bolts. It takes some maneuvering to get it out once it’s loose but it will come out without removing the lower control arm.
3. Remove the hydraulic pump. Remove the electrical connector. I couldn’t remove the smaller steel line on top of the hydraulic unit so I just broke it off. There is a bolt behind this line, it is the worst one to get to. I used a 10mm 3/8" drive socket with a knuckle/swivel and a few extensions or you can use a 10mm wrench from above where the reservoir is. Remove the other 3 bolts and the pump will come out the same way the alternator did.
4. Remove the hydraulic fan pump reservoir by removing the 2 bolts and two hoses.
5. Plug the hoses going to the cooling coil that is located between your radiator coil and the AC coil. There will be no pressure here, it’s just to keep excess fluid from leaking from the cooling coil. I just threaded a 3/8” bolt into the hose ends
6. Reinstall the alternator
7. Install the new shorter belt in the same way as the old belt. The upper idler pulley is smooth and the ribbed side of the belt will ride on the pulley. The shorter belt is a 99” or 100" x 13/16" 6rib v-belt.

The fan I purchased was a Flex-a-Lite 183 for a '03-'08 dodge ram. The brackets can be easily modified to mount the electric fan to the radiator. I still had overheating issues using the temp controller, I never could get it adjusted right so I just wired it to come on when the key is on and removed the temp controller. It works just fine. The fan comes with installation instructions that will tell you how to install and wire it and aluminum mounting brackets that are easy to modify to the shape you need. You will need to make a custom bracket if you want to bolt the ac canister to the new fan shroud. You also need to mount the aux heater pump to the new fan shroud with a screw or bolt.
After you install the fan, put the upper radiator hose back on and follow the fill and bleeding procedure for the coolant system.
The Flex-a-Lite fan is about as loud as the stock hydraulic fan on high. It cools my Ls perfectly, I sat in gridlock for 45 minutes on a 105 degree day and no overheating issues.
I also have not upgraded my alternator because the LS PCM will not allow it to charge properly. I have not noticed any problems with the factory alternator.
As far as wiring, you can attach the power wire of the fan to the large power wire under the fuse box in the engine compartment and attach the ground wire to a reverse polarity relay and use a switched power source to power the relay. I found a switched source under the dash, I believe it’s a green and orange wire under the steering column.
I also installed a toggle switch to turn my fan off manually. I did this for the drag strip, I turn it off as soon as I stage and turn it back on as soon as I hit the return road.
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I'm doing a complete change over from the Hydraulic fan to the electric fan set up. However, I'm having trouble removing the radiator from the engine compartment. This Bird has 3 coolers in it. One for the AC, one for what appears to be for the Hydraulic fan, and power steering, and then the Engine coolant radiator. I thought I was going to be able to remove the middle radiator, but it looks like it has to stay because its the power steering cooler as well. The tabs on the water coolant radiator that actually are the mounts of the radiator are hitting all of the other lines, not allowing me to remove the radiator from the compartment. Can someone help?? Is there a video out there addressing this issue? My bird has sat for about 3 months now, and I'm getting worried about her. I need to get this puppy fired back up and into action. I've bought all the parts for the electric conversion, so thank you in that regard.
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Warning: USE AT YOUR OWN RISK! FIT AND FUNCTION ARE NOT GUARANTEED! NO WARRANTY, EXPRESS OR IMPLIED, IS PROVIDED FOR THIS MODIFICATION! This is working OK for me, but we'll see what the Texas heat brings next summer.

Goal: replace gen I hydraulic fan system with the gen II electric. Want to keep the intelligent fan control functional. Yes, this can be done cheaper with aftermarket fans, but the controls are typically lacking. This integration allows the PCM to select the fan speed from very slow to very fast depending on conditions. You can also get to my full flickr feed of LS mechanical work w/ high res copies of the pics. No pretty pictures, sorry.

Stuff you need:
Gen II fan and wiring pigtails: note that 03/04 has two connectors while 05/06 has one. Wiring, colors and everything else is identical.
Alternator (possibly)
two sets of two pin weatherproof connectors
6 gauge wire, ring and butt connectors
18(ish) gauge wire and various connectors
Provisions for control mechanism of your choice (see below)

Electric fan basics:
The power and ground should be connected at all times. No relays or switches. Get a 60 amp fuse. The fan pulls 43 amps at full blast.
Big red and big black wires are obvious. The small green wire feeds power to the in-fan computer and is on in run and start for the stock install.. The white/black wire is the signal line that carries a PWM that instructs the fan on what speed to run. The really nice thing is that if the fan computer can't figure out the signal, it'll fail-safe to full speed. The signal line can be grounded, hot, floating, whatever, without damaging the fan. So if all else fails, just run the sucker full blast. Fan will only run when power is applied to the computer. Although, if it's bootstrapped, then power removed with the signal still connected, it can sometimes remain running. My initial install just left the signal wire floating. That is not a very good choice, however.

Other fun notes: fan pushes a significant ripple into the car's power rail when running full blast. Looked like about 1V @ 2khz (ish). Audio dudes beware.

If you have a bunch of accessories/options, then you'll need a stronger alternator. The stock is barely adequate for the car with all options. Big stereo? Get an alternator. Seat heaters? Get an alternator. My car does not have the heaters and only the stock radio, no other gadgets.

Remove old fan and hydraulic pump. Remove all hoses. Plug cooler inlet/outlet. I had to drop the a/c condenser to get to the outlet on the cooler. That took an hour alone. You do not need to disconnect the a/c drier, although you may need to loosen various hose mounts to get enough movement.

Connector and alternator:
While alternator is off, cut off the old actuator connector and add your own two pin connector. I did this after everything was back on, and it's REALLY hard to solder between the engine and the frame. Keep track of which pin is which. Green is power, Brown is signal.
Install alternator and new belt. My belt was 100 1/4" Gates - normal stock part at my local store.

Fan modification and installation:
See hydraulic fan vs electric Front:


Note that the hyd blades are much larger. This means it can spin slower to move the same amount of air, but is harder to turn. So the electric will spin faster - and be louder - compared to hyd. Electric does not have water pump mounts, but that's OK. A/C drier mounts just fine.
**ALL PROTRUSIONS ON THE PASSENGER SIDE MUST BE GROUND OFF!** Not the mounting tabs - the stuff for things to mount to the shroud. Anything that sticks out towards the engine. We spent a couple of hours trying to wedge it in there in various conditions, finally just ground down everything. For the Gen II, the DCCV actually mounts on the shroud. All that crap just bumps into things.
Make sure to get the tabs into the slots on the radiator. This is also much easier with the upper rad hose disconnected.

I ran the ground to the body bolt under the air box:

Be sure to clean under the washer to make sure it's bare metal. Hit it with a wire brush.
I pulled the positive along the big wire harness in the front. Got a MAXI fuse block from Wal-Mart - after trying three auto sound stores and Best Buy - and a 60 amp fuse:

Routed through existing harness:

Tied it into the big lug on the fuse panel:

I used 6 ga for the power lines to match those on the harness. The feed line to the fuse panel is a 4 ga, so it should be fine with this extra load. Again, YMMV. Be careful, monitor it for overload.
Run the signal and fan control power lines along the front and towards your new connector.

Control: The Simple Way
Add the opposite end of your connector type onto the fan wires you just ran. Green to Green, Brown to White. This will give you full fan any time the ignition is in Start or Run. This is an excellent fail-safe. So regardless what else you do, have this as an option in case things go nuts.
Problems: In the cold the engine will have a hard time warming up. This can be very bad for you engine if you do short drives in the cold. Extra power load when not required.

Control: The Slightly Effective, but Stupid Way
I was ill-informed at the time and made this monstrosity:

Tie the PCM power and signal to 85 and 86 (either way). Also tie PCM power to 30. Tie Fan power to 87. Put in a diode from PCM signal to PCM power to protect the PCM when the field collapses.
OK, WTF did this just do? I found that when the PCM requests mid to high power, it can throw a relay. So when it does, you're now powering the electric fan computer, and it'll run full speed.
Problems: This is REALLY STUPID because the relay will chatter as the PCM changes its control signal. This will kill the relay. The rapid field collapses might fry your computer (although I ran like this for two weeks fine). The relay will die quickly. Mine would stick on. But, for cold mornings, this left the fan off while the engine warmed up. A quick whack to the relay when I stopped the car reset it. Annoying, but quick, easy, cheap, and slightly effective.

Control: The Very Effective, but Difficult Way
Why, just adapt the Gen I signal to the Gen II signal. Easy!
Granted, I'm horrible with analog circuits, but I spent around 60 hours getting this to work. At least half of that was just me not being very good at analog work.
Gen I is a PWM, period of 10ms, ranging from 95% duty cycle for minimum speed to 10% duty cycle for maximum speed. The Gen I *switches ground* to make the PWM. Key note. If you hook up a standard multimeter you'll get some funny results (like a smooth resistance curve, which makes it look like it just changes resistance to ground, which can cause you to spent two weeks designing around that, just to learn that isn't what it's doing at all and getting really mixed up).
The Gen II signal has period 7 ms, ranging from 5% duty for minimum speed to 95% for maximum speed. Note that if you fall under ~5% duty then it'll lose the signal and run full speed.
I built a circuit based on the TI TL494. This can be done with any similar chip, and in lots of other ways.

I used a 50k pot on the voltage divider feeding DTC. It's set around 14k right now. Adjusting that changes when the output curve starts. I didn't get a perfect match (ie, 90% in = 10% out, 50/50, 10/90, etc), but pretty close. Changing this value lets you either delay when the fan engages - and reduce max speed - or engage sooner and get to max speed sooner. It's just a trade. I expect to adjust it again during summer. Upping the voltage divider by an order of magnitude might be a good idea. The PWM output resistor set can be higher - it was stable at 470 ohms, shaky above 600 ohms. The set of four 1k's is about 270 ohms (variance due to 5% resistors). Well within the 1/4 watt rating of the resistors, but may waste a bit more energy than required. The 1k load on the PWM input was also a complete guess. The input filter resistor/cap was determined by experimentation. That set is stable, but there may be better values. The timing resistor is the actual tested value I used. Any variation will change the output PWM frequency. I didn't try to test the timing capacitor for its true value, though. A scope is invaluable in testing.
I got a better curve match when using the feedback input, but that required an op amp voltage follower to buffer the PWM input filter and a different voltage divider. Way more complicated and used quite a bit more power, so ditched that idea.

And a few pics of the final piece. I added some rs232 pins for taps for testing.



I pulled ground from a body bolt on the shock tower then velcro'd the box to the side of the fuse box. Not the cleanest install, but easy to get to. Once I have a few months on it I may hide it under the fuse box.

This is working so well I may actually do something similar for my '72 Cutlass.

search engine help: fan swap gen 1 I to gen 2 II hydraulic fan replacement
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Update for the fan replacement. Per the car/truck powertrain control manual section KN10 instruction says to replace the fan motor. Turns out you cannot buy just the motor, you must replace the entire fan shroud with the motor and blade as an assembly, WOW that got expensive really quickly. My local Ford dealer quoted me a price of $1,214.75 and 6 weeks delivery time. This is the part ONLY no installation. Looking online I found prices of $1,323.00 to $648.19 plus shipping. This the quoted part for the 2005 bird. WOW I just want the motor. My ’96 bird had a bad fan motor, drilled out the studs, placed new bolts, two hours and $38.00 later all was well again. Not cheap just hate to waste money.

Turns out the only difference between the 03,04 and the 05 motor is the wiring. The shroud, blades and motor /controller are the same. The 05 has 1 connector with 4 pins and the 03/04 has 2 connectors. The conversion is straight forward, the large wires simply pull out and slide into the new connector. The small wires require using the original pin connectors, simply cut the original wires and and splice them to the new fan wiring. Ford changed the gender. I crimp with a real heavy duty commercial crimper, solder and seal everything up with adhesive shrink tubing at least 6 inches long

While I was at it I decided to replace the heater control valve, the serpentine belt and add new coolant, total cost came to $381.90. The last 2 parts were purely a matter of convenience as this area is very accessible with the fan shroud removed. The thermostat housing and all hoses were replaced earlier before the fan problem was diagnosed. The fan itself is for a 2004 and the price is $266.29. All parts came from Amazon.

I also drilled a 7/8 inch hole in the shroud approximately 6 inches from the electrical connector toward the center of the car, this allows me to see the fan spinning, without sticking my fingers in there.

Final test. Connecting an oscilloscope to the small wire FCV wh/bl shows nice square wave signal. the hotter the motor, the faster the signal rate, The faster the fan spins. My scan tool shows the temperature stays 207 to 214 degrees. I know it was done right. When I put new coils and plugs in I found the hard to get bolts on the valve cover spark plug coil covers were simply left out, the previous owner had service work completed by the FORD dealer.
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