Fan Clutch Replacement Write Up

Today I swapped in a new fan clutch on my 94 XJ, 4.0 with AW4. Sorry, no pics, but everything is pretty straightforward, so I don’t think the lack of pics will hurt. I used a new NAPA heavy duty fan clutch for the ZJ, which quite a few people have recommended. Symptoms were heating up in stop and go traffic (but not OVERheating) and the temp would come right down if I got on the freeway.

A comment on diagnosing the fan clutch – several people have said to try to spin it if it’s hot, and if it makes 3 –4 rotations while hot, it’s shot. I tried this and could only make about one rotation, BUT I also tried with it stone cold and could only make one rotation also, so I think the fact that there wasn’t any difference between hot or cold clutch may be a better indicator than the absolute number you can get with a spin.

On to the work:

Remove the electric fan. You can probably do this without removing the e-fan, but it’s only two small bolts and one electrical connector, and my hands are pretty big, so it gives a lot more room to have it out of the way. Two 8mm bolts at the top of the e-fan and the bottom is just two tabs in slots so it lifts out once the two bolts and out and the connector is disconnected.

Remove the two 8mm bolts at the top of the fan shroud. I’ve heard people say they can actually remove the shroud with the fan still in place, but I’ve never been able to do it on either of my XJs. Taking the two bolts out allows it to move around enough to get it out of your way while you are removing the fan.

Remove the 4 nuts that hold the fan/clutch assembly onto the hub/belt pulley. The nuts are 13mm, and there wasn’t enough room to get a socket in there, so I broke them loose with a box end wrench then took them off with a ratcheting box end until they were finger loose. I ran them off with my fingers, holding a magnetic pickup next to them so it would catch them and not let them drop down to the mud shield. Your belt should be tight enough to hold the hub in place while you break these loose. If not, you will need to tighten your serpentine belt to hold the pulley/hub while you take the nuts off. It’s tight in there between the engine and the radiator, so you just have to work your hands and the wrench around until all 4 are off.

You will now take the fan and clutch off as an intact unit. Be careful not to damage the radiator fins. You should be able to pull it off the front of the studs and pull the fan and shroud straight up and out.

Lay the fan and clutch down and take the 4 bolts out that hold the fan on to the clutch. They are 13mm head.

Mount the fan on to the new clutch assembly. Maintain the proper orientation of the fan front to back so the airflow is correct. On mine the torque spec was 18 ft. lb.

Take the reassembled fan/clutch assembly, put it in the shroud, and lower the whole thing in between the radiator and engine. My new clutch had slotted holes where it attached to the hub, so it was very easy to slip back on the studs. The pulley had tilted a little, but I got all the nuts started and alternated them until it was snug and everything was flat again. The torque spec was again 18 ft lb, but I could not get a socket in there to torque them, so I just used a box end and got them good and snug.

Re-attach the shroud and re-install the electric fan and you’re done. I started it and made sure the new assembly was tracking straight by looking along the front of the engine from the driver side fender.

Several folks have said this clutch makes for a loud fan. I think it is a little louder but I don’t find it objectionable at all. My in town temps are staying where they belong now.

Took me a little less than an hour, including time to drag out the tools and clean them and put them away at the end.

Hope this is helpful to someone.

Helps alot! I just changed my fan clutch after reading your write up. I had my Jeep (93 Grand Cherokee Limited 4.0) in my garage for other stuff and had the new heavy duty clutch just sitting there. So I read your post and installed it. Mine only took about 1/2 hour. Thanks for the motivation.

Now I can see if this heavy duty clutch will help bring down my temps.

Hallo. Nice write up.
To remove the old clutch, you need 1/2" a wrench?
I bought a very rare SO wrench especially for this job. (very long and slim).


What about the engine temp.? Is it now under 210F? How much in traffic and how much on the highway?

'92XJ

Nice write up. Information on how the new fan "spin tests" and temperature imrovement would be much appreciated.

Doing the cold and hot spin test really tells you nothing, when the fan goes cold the fluid in it drops to the bottom, thats why it roars when you first start it up, the fluid is being spun up and redistrubuted.
For a few years I ran with the bottom center section of the shroud missing, it was just U shaped with the two tabs still there, made for easy removal and reinstallation
When I replaced my radiator 2 months ago I had it all apart anyway so I used a new one I had on the shelf that I bought two years ago. I now have a ZJ clutch on the floor in the back, just need to get to it but the new radiator made a world of difference even in traffic and off road but then we have not broken 80F here yet this year so it has not be stress tested yet

wim hoppenbrouwers said:

Hallo. Nice write up.
To remove the old clutch, you need 1/2" a wrench?
I bought a very rare SO wrench especially for this job. (very long and slim).


What about the engine temp.? Is it now under 210F? How much in traffic and how much on the highway?

'92XJ

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I will have to do a "spin test" and report back. As to the temps:

When running the Jeep I can watch the temp gauge come up just to the 210 mark, then the thermostat obviously opens and it drops back down to what we'll call 190. Before changing the fan clutch, it would hang there if I was on the highway or moving along, but in stop and go traffic it would creep up over 210 to maybe 220 on a warm day.

Now it stays pegged at the 190 level (after rising and dropping to that when the thermostat opens) and does not even offer to rise above it, even at extended idle. It was about 90 here today (central california) and no temp rise at all. Definitely an improvement on cooling. I drove it quite a bit today and I really would not notice any increased noise except for the fact that I'm trying to hear it due to the complaints I've read about it.

The 220 I was seeing may not have been disastrous, but it was indicating to me that there just wasn't enough air flowing in town. I'm hoping to head out toward Mojave in a week or two, and I want to feel confident it won't overheat out there in the desert.

Thanks for the write-up. I just replaced my fan clutch at it was really helpful.

Hope you like listening to the fan spin all the time.
I installed the same Napa fan last summer and saw a loss of mileage on freeway driving. It kept the engine too cold on cool mornings.
After three months and a few thousand miles, I went back to the quiet stock fan, realizing it was not the right clutch for a DD
It did work well for hard uphill climbs in hot weather. Now I just manually leave the electric fan on.

You're talking about number of spins. What do you mean? Are you constantly rotating it with your hand until it stops turning? Or spinning it and letting it freewheel?

I thought my fan clutch was bad because it was easy to turn by hand when hot, and someone on another forum said it should be really difficult to turn. I got a new one and it does the exact same thing. I can spin it by hand very easily, but it stops as soon as I stop turning it.

I just finished up my fan clutch replacement using the ZJ clutch(48 bucks out the door at my local napa). My original clutch I wasn't sure to be bad really, just figured why not upgrade and do something I've never done before. My old clutch when hot or cold I couldn't get to spin an entire revolution, it would maybe go half. I thought that was enough of a sign to just replace it...

Mine didn't go as smoothly, I expected troubles though as it's something I've never done before ha.

I used this as a reference and was good to go until I went to put the new clutch/fan on. It was to thick to fit past the mounting studs, it was maybe 1/3" too thick. I thought about removing the studs then putting the studs back in. That seemed like it would be a hassle after I took one out and saw what a pain it was to get it out and back in. I did notice my studs where threaded longer on one side. I thought about flipping the studs so the short side was facing the radiator. I was worried about them sticking out too far in the back and hitting the pulley mount.

I decided I just needed a tiny amount of space so I figured I could tilt the radiator and get the clearance I need. Off came the upper radiator support(one day I'm gonna replace those 4 torx bolts though!) and sure enough tilting the radiator gave me plenty of room. I mount the fan/clutch and shroud all in place and I have plenty of clearance all around.

Bolting the clutch to the pulley was a bit of a pain, I need the long wrench show above for sure or the new ratcheting crescent wrenches would have worked well too. I was getting maybe 1/10th of a turn with a box end wrench, my ratcheting box ends wouldn't fit with the new clutch. I got them all nice and snug alternating around so it would seat evenly, the serpentine belt held it in place nicely. Then I got the E-fan back in and triple checked everything before firing it up.

First time firing it up was impressive, it is loud with your head under the hood that's for sure. It also sucked enough air that it slammed the door closed that was in front of the XJ! I never had the door slam before from a fan lol. Sitting inside I really didn't notice any difference, I didn't drive it yet so I'll see tonight. I don't see the noise being an issue for me though, with the poly motor mounts, flow master exhaust and radio going I won't hear the fan.

Thanks to everyone though suggesting this upgrade and the write-ups it all helped me a lot. When I have to do this again(which I hope isn't soon) I think I could do it in 30-45 minutes. I would also look to replace the studs with shorter ones and I also need to cut my fan shroud in half and figure out a way to mount the pieces together. I want the complete shroud but I want it as 2 pieces and easier to remove!

I removed/broke the bottom of my fan shroud, that left the fan shroud upside down U shaped and left the two mounting tabs to hold it in place. Ran it like that for 3 or 6 years with no difference in temp. I did eventually pick up a new shroud and put it in when I replaced the engine.

RichP said:

I removed/broke the bottom of my fan shroud, that left the fan shroud upside down U shaped and left the two mounting tabs to hold it in place. Ran it like that for 3 or 6 years with no difference in temp. I did eventually pick up a new shroud and put it in when I replaced the engine.

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I'm thinking it should be easy enough to cut the shroud horizontally and just make some tabs to hold it together. Undo a screw on each side and the shroud will split into 2 pieces leaving it fully intact.

After driving for about 45 minutes this evening in stop and go traffic and about 93 degrees out I got my initial impression.

The temp got to the 210 mark just as quickly as before, right about when I was leaving my neighborhood and getting on a main road. The AC was ICE cold now, normally I leave it on Max for a long time and it was cold but not freezing. Tonight I turned it down cause I was actually getting cold with it on Max. The temp stayed pinned right below 210 and I mean the needle was just touching the 210 mark so it was prolly 209 1/2 *.

The noise wasn't an issue at all, I didn't notice with the windows up and the Ac going. Later I put the windows down and couldn't tell it was any different. Seat of the pants dyno showed no sign of gain or lose.

I did a spin test once I got home, turned the motor off and went to spin it and it has resistance. I can turn it by hand easy and it turns smooth but I can't spin it and let it free wheel at all it stops immediately.

I just did this following the writeup, thanks a lot.
I do have some slight squeaking over 3000RPMS though. The clutch is tight and the belt is tight. Am I missing something?
I didn't mess with belt tension while doing it.

Check the belt tension.

I am looking to replace my fan clutch. Are the ones from Auto Zone or O'Reilly's pretty good or should I be looking at dealer for long life and proper cooling?

I am looking to replace my fan clutch. Are the ones from Auto Zone or O'Reilly's pretty good or should I be looking at dealer for long life and proper cooling?

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I don't know, everyone here seems to recommend napa so that's what I would do. I would go ahead and get the ZJ clutch, mine is noticeably more loud though.
If that's not your speed, just get the XJ clutch, again from Napa IMO.