Electric Fan Install
After some deep mud runs, I decided that I didn't like the mess in the
engine
bay of my 94 D90 created by the engine driven fan. I also had some cooling
problems at times due to the radiator getting all clogged up with mud. I had
seen that others successfully installed the Flex-a-Lite 210 dual low profile
fans.
I liked the idea of being able to shut them off when water crossing and the
added room I'd get in the engine bay so I decided to give them a try.
I purchased mine from Summit Racing along with the optional adjustable
thermostat relay switch.
As part of the electric fan install, I also removed the air conditioning. I
never
used it and it was hard to remove mud that got trapped between the AC
condenser and the radiator. The first step was to remove the AC stuff and
the radiator from the rig. While I was at it I decided to replace all belts
and hoses. I was also installing a 160 amp alternator, a Rockware bumper,
and a set of Hella horns. Additionally, I would be relocating my turn
signals.
Since I was doing so much work, I removed everything in front to make it
easy.
Once I had the radiator out, the first thing to do was figure out a mounting
system for the fans. The fans come with these long plastic bolts that you
can stick through your radiator to secure them. I didn't like these
at all and wanted something that would let me get the fans in and out
easily. I got my idea from the stock fan shroud. I liked the way it slipped
under a set of tabs at the bottom of the radiator and was secured at the
top with 4 easy access screws. My fans would have to go in this way.
The fans are much thicker than the stock fan shroud so the first thing I did
was bend the tabs at the bottom of the radiator out so I could add some
metal
to them later.
They were hard straighten just by bending, so I cut a piece of 2x4 to
just the right length so I could use it as a buck to hammer them into shape.
The width of the fans is a good match for the width of the radiator, but
they
are a little shorter in height. So, some metal had to be added to the
radiator
to make it slightly smaller in the vertical direction. I used two pieces of
1/8 " thick
aluminum bar stock, 1 1/2" at the top and 1" at the bottom. The sides of the
radiator stick out a little from the top and bottom, so the addition of the
aluminum pieces also had the added benefit of creating a perfectly flush
mounting surface for the fans all the way around. I made the pieces up,
clamped them into place, and used a larger scrap piece of aluminum
bar stock to make sure I did not damage the radiator cores when the
drill poked through the metal. I then pop riveted the pieces into place.
The fans have 4 ribs on them, two on top, and two on the bottom. They
are there for use by some optional supplied mounting hardware, but
were in the way of what I had planned. They had to go, so I ground
them off.
Now I was ready to attach my lower mounting bracket which I made out of
some 1/8" thick 1"x1" aluminum angle stock. I clamped it into place onto
the tabs I had straightened at the bottom of the radiator so that it would
compress the fan seal a little when the fans were slipped into place.
I drilled three staggered holes in each tab and pop riveted it into place.
My lower mount was now complete.
For the top bracket, I would need an "S" shaped piece of aluminum
stock. I couldn't find any, so I made my own out of 2 pieces of the
angle stock I had used for the lower mount. I had to slot it in 5
locations so that it would sit flush against the piece of aluminum that
I riveted to the top of the radiator. Without the slots, the heads of the
rivets would keep it from fitting correctly. I then drilled four larger
holes through everything for the bolts that I would use to secure
the upper bracket.
I would use rivnuts in the frame of the radiator to hold the bolts. I
decided that the aluminum piece that I added to the top of the
radiator was not a good place to put the rivnuts, so I drilled out
the pop rivets and installed the 4 rivnuts right into the metal of the
radiator. I space the rivnut holes evenly between the pop rivet
holes.
Finally, I pop riveted the 1 1/2" bar stock back onto the top of the
radiator, slipped the fans into the lower mounting bracket, and
bolted in the upper bracket. It came out just as I had hoped it
would.
Now it was time to put the radiator back in the rig. I removed the
fans and placed the radiator onto the mounting brackets making
sure that the pins were in the rubber donuts. Then I reconnected
the oil lines and hoses. Wow, look at all the space I now have to
work on the engine when the fans are out.
Before I continued, I took care of the turn signals. I'm showing it
here as an example of other connections that I made. I always
stagger and solder the connections an then cover with heat
shrink tubing and then electrical tape.
While I was on electrical stuff, I decided to take care of that part of the
install. I didn't like the thermostat that came with the fans. Too
complicated
and sloppy to install. There had to be a better way. Since I no longer
was using the AC, I looked at the AC cutoff switch that's screwed into
the thermostat housing. It's normally closed and opens when the coolant
hits 228F to kill the AC if your rig is overheating. It also looks an awful
lot like a standard automotive fan switch. I took it out and headed down
to the local autoparts store and selected a fan switch that looked like a
good match. When I got home I found that the threads were just
slightly different so it wouldn't screw into the thermostat housing. So
much for doing it by eye. Undaunted, I removed the thermostat housing
and headed back to the autoparts store. After going through lots of fan
switches, the parts guy and I finally settled on Beck/Arnley part no
201-0809.
It's a VW fan switch with on/off settings of 198/189F which goes perfect
with the 190F thermostat used in the D90. Here's a shot of it installed in
the thermostat housing with the AC cutoff switch on the left.
Since I had the housing out, I installed a new thermostat as well. It's
very important when replacing the thermostat that the little pin valve
in the thermostat is at the 12 o'clock position.
I then installed put the thermostat housing back and wired up the switch.
I ran the wires through the factory harness over the top of the alternator
and towards the coil where they joined up with the 10g power lines to
feed the fans. This makes for a very clean install.
I ran the single harness with the power and control lines into the battery
box
where I temporarily rigged up a Hella 30 amp relay and fuse for the fans.
I will be putting in a power distribution panel later at which time I'll
wire it up better. I also plan to use a separate relay and fuse for
each fan so in case one goes, it won't take both out. I will also
put in a 3 position switch with positions for always on, auto, and
always off. For now, I just pull the fuse for a deep water crossing.
Once the electric's were taken care of, all I had left to do was
put the fans back in and button up the rest of the front. The fans
were not as easy as I had hoped to get in. With the hoses in place,
you have to position the fans just right to slip them into place but it's
still fairly easy once you get the hang of it.
With the nose put back together and my new Rockware bumper and
cool red Hella horns, my rig was ready once again to hit the trails.
The new cooling system worked flawlessly. The fans cycle on and off
exactly as expected and maintain perfect operating temperature. Since
my temporary wiring has them always on, they continue to cycle on and
off a few times after I shut the rig off. It's kind of neat to see the rig
continue
to cool itself this way. I've got a dual battery system in the works so I'm
not worried about killing the battery if the fans cycle on and off too much
when the engine is off.