rivman05

Afternoon folks,
I am in a bit of a pickle, I punctured the radiator on my 01 WJ 4.7L crawling through about 1-2 feet of water and ice (yeah I know it wasnt smart), and am trying to figure out how to tear it all down. I have the FSM and have looked at it, but is there a way to replace the hydraulic fan with the an electric or pair of electric fans? Also what would that all entail as it was originally not meant for electric fans. Anyone try this? Im just curious as I am trying to see if there is a better way with less hydraulic hoses to worry about.

dave1123

The 4.0 WJs have only electric fans, although the tow package ones also have a clutch fan. The 4.7 with the hydraulic fan was an experiment to use wasted pressure from the power steering pump to lighten the load on the alternator and electrical system. You can bolt on the electric fan from a 4.0 complete with shroud. The problem is controlling it. Without the hydraulic fan, it will set a trouble code.

There are 2 types. One has 2 wires and is controlled by a pulse-modulated relay switched by the PCM reading the temp sending unit, the other has 3 wires, high and low, controlled by 2 relays switched by the PCM in the same manner.

When my pulse-modulated relay **** the bed, I rigged a switch and relay to it and had it run on high until I got a new relay. It needs a relay because it pulls around 30 amps or so. Many people on this forum have used aftermarket controllers and have write-ups posted. Bustedback was one that I remember as being very good because he followed up. You may need to swap the power steering pump to an earlier 99-00 pump because of the solenoid valve on yours.

The way the system works on my 00 WJ is the fan doesn't run at all until the engine gets up to 210*, then it kicks on high. It runs on high until the temp drops to 195* then switches to low and runs as long as the ignition is on, unless the temp goes up again. Then it switches to high until the temp drops again. It will continue to cycle like that.

That hydraulic fan is an expensive nuisance. Some engineer's reason for existence.

On other thing! The electric fan is a permanent magnet motor and will run perfectly well in both directions. Make sure it's pulling air thru the radiator, not pushing it out the grill. rockauto.com has the complete fan and shroud for around $70-$80.

rivman05

Thats what I wanted to know, I am not towing anything, and with it never getting above 80 degrees here I dont think I need a fan that runs all the time.

dave1123

Oh you will. Without any airflow thru the radiator, it gets hot REAL QUICK! I find even at single digits in air temp, my fan cycles when I'm sitting idling.

You may not have this problem, but the main reason cars overheat while sitting in stalled traffic is because the stalled torque converter generates A LOT of heat. If there's a accident or other long waiting period, it's best to slip it into neutral whenever you can to prevent this.

My thought would be to use a double pole, double throw relay with a temp sensor in the upper hose to control it. Have it wired to run on low always and on high when the temp sensor trips at 210*. That requires a fan with 3 wires. It will require a single trip relay for the sensor itself because of the load the fan draws. I think my fan is fused at 40 amps. If you've got the room, you could make it simple and install a clutchfan to take care of the low speed function. There's plenty of room on my 4.0 but IDK about your 4.7.

A lot of people have done this conversion, but nobody has said anything about fooling the PCM to not set a trouble code because the hydraulic fan isn't there.

rivman05

There is only 7 miles of paved road, and 21 miles total in Bethel. Its not usual for an accident to hold stuff up, but I think what I should have said that I dont need the fan running if it is not at least to 185.Once its close to temp I have no beef with a fan running, but dont need a fan coming on trying to pull air through when its trying to warm up to 185 or so. It is a hassle tho tearing this thing down. I have a radiator ordered so hopefully in a week Ill be back on my feet.

dave1123

No, off your feet and back on your seat! Oh, and try to stay away from the ice?

That traffic comment wasn't for you, but for others for common knowledge. Your thermostat should bring it up to temp anyway weither the fan is running or not.

rivman05

Yes, I used to think folks were full of it when they told me ice was one of the most destructive things a person can find. True about the thermostat bringing it up to temp. Hopefully things cool back down to about 10. I am working with our welding kids and the cad kids to have them work together to build this bumper:

https://flatland4x4.com/product/99-0...-winch-bumper/

rivman05

Well I have got my WJ back together, and looking at doing the 99-00 power steering pump and 4.0 fan setup. Does anyone know if a tuner can turn off the code for the hydraulic fan after being removed? I do not want this thing to crap a seal or some other issue and have no fan while out on the river. I took it 50 miles down river this weekend to bring the family ice fishing....I dont need it to crap the bad on a trip like that.

Peter1969

rivman05

I have a few obd2 scanners, and clear the codes. That is not the same as turning the code off tho. Some engine tuners can turn certain cels off in software and when its burned back into the rom the codes will appear. I used to do this with RomRaider on my Subaru and Integra when I was younger, and had access to a dyno, wide band o2 etc.

dave1123

Oh, I'm sure it can be done. IDK how though.

blueseasons

There is another possible choice. Dorman 620-149 12 blade fan and a Hayden 2794 fan clutch. This combination will get rid of the hydo setup you have now and you won't need an E fan at all.

dave1123

You're missing the point. It's trying to fool the computer into thinking it's working that's the problem.

rivman05

Yup Dave nailed it on the head, and Im not sure if the missing fan solenoid will send it into limp mode or not, but I am guessing it would.

dave1123

Okay, here's a trick I used on my old Datsun. Leave the solenoid attached to the harness and hang it someplace. That way the computer thinks it's working, and it is, but not doing anything. Might work.