Viscous Fan

ChileanKJ · **Posted:** Fri Feb 09, 2007 4:39 pm

I have 47500 miles (76000 km) on the clock with out any problem at all, until last month, at first a chirp sound like the serpentine, but i didn't find it, now i found it, the viscous fan is hard to move, so it is always engaged, i have to take it out, my service manual is for the 2003 gasoline and no viscous fan on it, the viscous is in CRD 2004, anyone knows how to take it out? a service manual photo? can the electric fan take over while i change the viscous one or two days with 30 °C outside on the meter ?

thanks

Claudio

Joe Romas · **Posted:** Fri Feb 09, 2007 7:27 pm

It says to remove the fan, clutch and shroud at the same time. The clutch unscrews from the waterpump and they have a special wrench for that. It's a RIGHT HAND thread. When all three peices are off then remove the fan from the clutch

Hope this helps.

ChileanKJ · **Posted:** Sat Feb 10, 2007 1:21 pm

Thanks for the info, today i taked out and it shows signs of leaks, aditional info for others, you have to loosen the top cross member to take the shroud out, it have a rubber on top of it that goes under the top cross member.

thanks

Claudio

Deezel · **Joined:** Sun Nov 27, 2011 10:37 pm **Posts:** 12

This message is for Joe Romas or anyone who can help. What kind of spanner wrench is used and can I get one from Sears or an auto store? Does heating up the RIGHT handed thread help in this process? Before I found specifics (at Lost Jeeps) I tried to remove the viscous nut thinking it was a left handed thread and probably torqued things the wrong way at first but I didn't have proper tooling (spanner wrench) available. Any help appreciated.... BTW, I'm not a noob but rather a 44 old guy who has wrenched in the past on a lot of things like commercial aircraft and cars...I've done a few timing belts in my day (gassers) and know how things work. I've since moved into management and have lost some of my abilities which only makes me respect the guys who do the hands on work these days! I have to do jobs like this to save money to support my 4 kids and wife....to keep what I have running as apposed to paying high dollar for mismanaged dealers... thanks a bunch.

msilbernagel · **Posted:** Sat Apr 07, 2012 4:40 am

36mm - I use one I picked up for the Dodge Cummins we have in the other rig; same size. I'd call around since many (if not most) auto parts places carry various economy versions of 'miller special tools' (etc).. i.e. specialty stuff. That size should be common. I think that's where I got the monster I use.

Also - if you check out the timing belt threads, since everyone has to remove the fan to get the job done they all give you some ideas of how to keep the hub from spinning while breaking that nut loose.

There is a bolt head underneath the hub that the fan screws onto - at about 4 o'clock - you might try a 15mm or 17mm (can't remember which) 1/2" drive socket, perhaps with a short extension. You can hold it there by hand (socket on bolt head) the outer circumference of the socket just fits those holes around the hub, so it can hold nicely. I've seen others put a large hex wrench (the 'L' shaped ones) through the holes so that it snags on the cast iron behind the hub and stops it from spinning.. other's have found or made the 'Y' shaped wrench to hold it. Guess you get to be creative with whatever is at hand!

Once the wrench is in place, smack it good - that seems to help shake it loose...

Good luck!

papaindigo · **Posted:** Sat Apr 07, 2012 9:31 am

Couple of things:
1. for those of you looking for FSMs go to Sir Sam's NOOB guide for a link. There are manuals and parts books for pre-2005 KJs that should be helpful. If you want the 05/06 manuals download both as the 05 lacks diesel cooling data, diagnostics but has illustration keys while the 06 is the reverse.
2. yep 36mm, I have the Lisle pnuematic kit others have used a really big crescent wrench from like Harbor Freight. Whatever you use you will need something to keep the fan from slipping on the belt. Options include a "Y" shape holder where a flange off the end of the "Y" will engage in holes in the fan hub base, a really long screwdriver wedged into the base and held by someone, or a 3/8" or slightly larger hex key short end inserted in one of the 2 small holes in that hub to catch the bolt head msilbernagel mentions. For a picture of the latter see http://www.beesvillebeefarm.com/jeep.html . Scroll down to the picture right after the one of using a palm nailer as a hammer.

Be very careful (a towel for piece of cardboard helps) not to puncture the radiator removing the shroud/fan. Other thoughts:
1. the 2 nuts that the shroud bolts screw into just "sit" in an open retaining fitting. Best use a bit of hot glue or a couple of wire ties to make sure they don't fall out. CRITICAL - be sure the keep track of the bolts that go into these nuts as length is critical; too long and you get holes in the radiator.
2. while the shroud is out consider modifying it to make future access easier. Options 1) cut in half below the bolts and leave bottom half off or 2) variations on the Aussie mod see viewtopic.php?f=5&t=66086&p=726546&hilit=aussie#p726546
3. for future ease of fan removal use to anti-seize on the fan hub threads.

naturist · **Posted:** Sat Apr 07, 2012 10:50 am

I highly recommend using one of the Hayden 2905 heavy duty clutches instead of original when you do replace that clutch. The original ones wear out so fast, plus even when working properly, they engage a bit too hot. 190˚F vs the 170˚F for the Hayden. That extra 20˚ will help a lot to keep things cool when towing or under heavy load in hot weather.

Deezel · **Joined:** Sun Nov 27, 2011 10:37 pm **Posts:** 12

Thanks all for the quick help...still no luck but I haven't tried everything mentioned yet. I am really skeptical of whether or not this monster nut is right handed thread versus left hand? The way the fan turns it doesn't make sense for this nut to be right handed thread. The way I see it, the fan turns clockwise if you are facing forward (driver seat) so why would a right hand thread be needed? Also, a handy link for the electric replacemnet fan would be AWESOME! Thanks again and Happy Easter all!

Deezel · **Joined:** Sun Nov 27, 2011 10:37 pm **Posts:** 12

OK I'm an idiot! and getting old and rusty at wrenching... I answered my own question. I confused what right hand and left hand threads really are. When someone stressed that the fan clutch was a RIGHT hand thread, my brian thought oh this is the oposite of what's normal and I forgot that RIGHT handed thread is normal.....ugh.

papaindigo · **Posted:** Sat Apr 07, 2012 12:20 pm

Don't feel bad. I find it much easier to think standard thread=counterclockwise to remove vs. reverse thread=clockwise to remove as opposed to right/left hand and don't even get me started on what to do when I'm on the opposite side from where things come off.

Bottom line is this was put on "dry" at the factory and has been tightening every engine rotation since then so it's on there really really tight but how tight varies between vehicles. lgoodbar's at 100K miles came off pretty easy with the Lisle tool and a screwdriver holder but mine at 44K miles took the allen wrench stop trick and some significant Lisle tool pounding.

geordi · **Posted:** Sat Apr 07, 2012 3:33 pm

"came off easily at 100k"

<Han_Solo>Easy, you call that easy? </scoundrel>

I think it only SEEMED easy b/c we were beating on it pretty hard, and that screwdriver helped apply a fair amount of opposite torque in there. Yours might also have seemed harder b/c you had to do both sides at the same time, it does help to have 2 people fighting with that thing.

I'd be curious to see exactly how much help the anti-seize aluminum paste offers on future removals... At least you don't need to gorilla the thing when you put it back ON, it will never unscrew itself in normal operation - That hub is spinning to constantly tighten the nut. Just snug it up and call it done.

papaindigo · **Posted:** Sat Apr 07, 2012 4:24 pm

All is relative and I said "pretty easy". With the allen wrench in the hole and fully locked against the hidden nut the Lisle tool took noticably longer to start the loosening of the nut on my vehicle. Now I'll cheerfully admit there was significant single person fumbling around to get the allen wrench in the right spot and locked down.

I did try the screwdriver trick but that's definitely a 2 man job.

Lancer · **Posted:** Tue Apr 10, 2012 6:30 pm

Ok - I'm getting confused (happens to me this time of night); so to get this nut off (when I come to do it) it unscrews anti- clockwise yes? As normal in other words?

Deezel · **Joined:** Sun Nov 27, 2011 10:37 pm **Posts:** 12

Lancer - Yes anti- or counter clockwise...as per normal is how this beast comes spins off. The threads are standard and not reverse. don't do like I did and try the other way and make matters worse..LOL!

tonycrd · **Posted:** Wed Apr 11, 2012 11:46 am

What do you need?...

4"-3/8 socket extension to hold the pulley

5 feet of 2" pipe to hold 3/8 socket extension

36mm wrench

BFH

2 guys

6 beers

:wink:

Sir Sam · **Posted:** Wed Apr 11, 2012 12:55 pm

FYI I have a pretty good amount of information on how to get the viscous fan off here:

http://colorado4wheel.com/content/KJ_TB.html

Viscous Fan

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