Electric Fan Conversion on an 89 YJ - submitted by Laybackman

I have an '89 YJ with a 4 banger coupled to a five speed tranny. I had a water pump self destruct after a year. I had about 3000 miles on the pump. After poking around under the hood I discovered that the clutch fan wasn't doing any more clutchin' so my thinking is I essentially had an unbalanced fan tearing up my water pump. I figured it was time to do a mechanical fan delete and attempt to rig up an electric fan for cooling. It would also free up the horse power used to turn the fan.

I have an '01 GC also and it has an "S" style electric fan and decided that it would fit the YJ's radiator or I could make it fit. It also runs very quiet. I missed out on one listed on EBAY that went for 60 bucks and could not find one used locally. I decided to find a new fan on EBAY. I ended up buying a new Zirgo fan. It is the "S" type fan that is 16" in diameter. It pulls 3300CFM which is big air for the four banger. This fan could keep a small block V-8 cool. They usually go for $199.00 plus shipping. I scored one for $149.00 shipped. Pricey, but it is new and dependable and cooking a motor by going el cheapo on a fan is bad economics as I see it.

Next comes disassembly. Drain your cooling system, pull the upper radiator hose, fan shroud, unbolt and remove the fan then replace the four bolts that held the fan pull the lower radiator hose and then the radiator. Unscrew the snout that comes out of the intake manifold that held the bypass hose. You will have to cut the stem or it will not spin by the throttle linkage. Disassembly is completeI installed the fan on the radiator using 1/4" x 20 hardware. This one came with the four brackets that holds it in place:

Next I decided the sender would make contact (close) when the water temperature hit 180° F. You will need a 40A relay an inline fuse holder, the socket assy to get out of the sender and a 20A fuse. See pics at right.

These 4 parts cost about $45 bucks.

Here's a list of the parts I used to do this:

NOTE: FIP = female pipe thread MIP = male pipe thread

It is tight coming out of the intake manifold because of the throttle linkage being right above that spot so I used a 3/8" MIPx3/8" FIPx45° elbow screwed into the water jacket of the manifold to get away from the linkage. Next I used a 3/8" MIP short nipple, a 3/8" FIPx45° elbow, a 3/8" x1/2" FIP reducer, a 1/2" MIP short nipple, a 1/2"x1/2" by 1/2" FIP "T" to screw in the sender that was 1/2" MIP threads. It is located at the end with the socket assembly plugged into it. To get the water hooked back up I came out of the "T" with a 1/2"x3/8" FIP reducer bushing, a 3/8" MIPx1 1/2" nipple , a 3/8"x3/8" FIPx45° elbow, and finally a 3/8"x1 1/2" MIP nipple. I used pipe dope to seal the threads. Don't use too much, it could foul your cooling system. Now I just attached the hose from this last nipple to the thermostat housing. Now I filled up the cooling system as best as I could and checked for leaks. So far so good. These fittings cost about 8 bucks.

Now using this schematic supplied with the Zirgo fan (see photo at right):

I wired the fan using 12 gauge stranded wire instead and made one additional change. Note the wire that goes to chassis ground for the fan. That is where I cut in the sending unit.

NOTE: The only sending unit that my local auto parts man found for me that made contact (closed) at 180° F had 1/2" MIP thread. If he could have found one that was 3/8" MIP thread that closed at 180° F, I would not have had to adapt up to 1/2" pipe and then reduce back to 3/8" pipe.

I went directly to the battery for my power to pin #30 and #86 on the relay with the 20A inline fuse to protect the relay. I ran both the ground wire for the relay and the ground wire that comes out of the sender back to the negative battery terminal battery. I think it is easier to check for a bad ground that way since this fan is keeping the cooling system happy. Now install the 20A fuse. It will not run if you don't. You know how I that found out don't you.

Next I took it for a shake down run. I drove the YJ about 10 miles with a stop for gas during that ride. Normally my temp gauge never gets over 210° F. That fan kicks in precisely when that happens. Nice coincidence! Now with this set up the fan will run after the ignition is off since it is wired directly to the battery. It ran for 30 seconds and then turned off. Later on I topped off the cooling system and took it for another ride. It did the same thing again.

To summarize the installation it went easy enough. I needed only hand tools to do it. The engine is definitely running much smoother with that POS clutch fan gone. There is definitely more power also. Horse power stats for the four banger is 123 ponies at 5250 rpm's ( That's about 5 seconds 'til it tosses a rod) what kind of pony power are you getting at 2000-3000 rpm's 85 or 90? If I can get 5 or 6 horse power added to 85-90 ponies that's a 6% horse power increase out of a four banger for about 200 bucks in addition to the smooth running motor.

I believe that you can alter the way I wired this relay up so the fan will shut off when the ignition is turned off. I think that you have to run power to the relay at pin #86 from an ignition circuit instead which would disable the fan when the ignition is turned off BUT I could be wrong. I decided that I wanted the YJ not experience a heat spike after turning it off. So the way it is set up will prevent that.

Hey I hope this helped you out!