Almost every automobile manufactured today uses an electric
fan for cooling the radiator. For the Mustang, Ford went this
route in 1994. The electric fan uses less horsepower than
the mechanical fan, helping both gas mileage and acceleration.
You know which part interests us.
We came across an interesting alternative to the costly aftermarket
electric fan kits; a junkyard fan out of late 80's, early
90's Taurus cars with the 3.8 liter V6. It is a two speed
fan with integral shroud and a low-profile electric motor.
One Mustang owner is using his on a supercharged 302 without
any problems. Sounds like it should be able to handle our
naturally aspirated 302. We headed to the junkyard to find
our diamond in the rough.
Once in the Ford section of the yard, we were nearly overwhelmed
by the site of so many Tauri (plural for Taurus, isn't it?).
We chose an '89 wagon with the 3.8L V6 as our donor. A few
small bolts and one unplugged connector and the fan slid out
easily. We also pulled out over a foot of the harness with
the mating connector and cut the wires so we would have plenty
of length and a nice weatherproof connector.
The price? A mere $27, including the $2 entry fee.
With our dusty treasure in hand we headed to the local chain
autoparts store for a controller and a mounting kit. See side
bar for required installation components.
The stock 5.0L clutch fan and shroud were removed and we laid
the new fan in place to check the fit. The shroud covers over
80% of the radiator
|Junkyard Electric Fan
: Parts List
|Imperial Mount Kit
|Bosch 150amp Relay
||PN: 0 332 002 156
and sits nicely on the existing mounting clips at the bottom
of the radiator. Two "thru-core" connectors would
be needed to secure the top of the fan shroud against the
radiator.. To insure a good seal at the edges of the new shroud
we used foam weather seal you can find at any hardware store.
The pictures tell the story. It will also protect the radiator
from rubbing due to vibration.
With the fan in place we connected the cut harness we saved
and tried out the fan by going across the battery with the
bare ends of the wires. The low speed wire contacted the battery
post and the fan spun up quickly. The airflow felt very good.
If this was the low speed setting, what would we get from
the high speed? We wish we had CFM ratings for you, but we
could not find them in time for this article. We can tell
you that with the high-speed wire connected the fan was moving
a huge amount of air. Far more than the last 16" electric
fan we bought from the auto parts catalog.
Since the fan controller has only one relay we decided to
run just the high speed, which should insure a cool radiator
no matter what. But before the wiring can begin the charging
system will need to be upgraded. The stock 75amp alternator
will not be able to handle the added load of the new fan,
especially after we saw how much air it can pull. You can
check out the 3G
alternator upgrade here.
Using a Fluke digital clamp ammeter, we tested the starting
(or inrush) current draw and the operating current draw. The
Taurus fan pulled a little over 130 amps on startup (only
for milliseconds) and settled down to right around 40 amps
using the high-speed wire. This is why you must upgrade to
the bigger alternator and a Bosch high-powered relay.
Fan Wiring Diagram
The diagram shows how to use the fan
controller to fire the Bosch relay. A reverse current blocking
diode (or freewheeling diode) is a good idea on any motor
control relay. Once power is removed from a DC motor it becomes
a DC generator and the reverse voltage spike can shorten the
life of the relay. The diode will bleed this spike to ground.
The 1N5408 diode can be found at any electronics store for
just a few dollars.
The fan controller also has a lead that can be connected to
the air conditioning compressor clutch power wire to turn
on the fan whenever the A/C is turned on. If you wish to have
a manual control switch for the fan, simply connect it to
12V and contact 86 on the Bosch relay.
The last step is to set the electronic thermostat for proper
operation. With the engine running at idle, we let the temp
gauge slowly climb. We adjusted the small potentiometer on
the controller so the that the fan would come on just before
200*, which is after the coolant thermostat opens (180*, in
our case). This way, if you are cruising down the highway
and the thermostat opens but the radiator does not reach 200*
thanks to the steady airflow, the fan stays off.
So, how does it work? We decided to really test it by driving
6 hours one way in 100*+ temperatures and race at Los Angeles
County Raceway in Palmdale, CA. That is desert country west
of LA. Not only did it work, but the temp gauge never went
past ½ scale. Even letting the car sit intentionally
for over 40 minutes with the A/C blasting while we packed
up after the race in over 100* heat the gauge not only was
stable but dropped to only about 1/3 of the scale! The A/C
actually blows colder than before, even when the mercury goes
past triple digits (way past, occasionally).
Another pleasant side affect has been a 1 to 2 mile per gallon
increase in fuel economy on the highway. The fan isn't running
while cruising unless you turn on the A/C. And then it cycles
with the A/C clutch. In conclusion, the time and cost were
absolutely worth it. We can also run the fan in the staging
lanes by turning the ignition to the on position and switching
on the A/C. Just don't forget it's on and kill your battery.
We had to get a push start in front of all the other racers
Source for the Bosch Relay- Brandon
Products Group, www.bpg-inc.com