While pulling my water pump yesterday I got a good look at my fan clutch. I think it is the OEM clutch. This clutch is built like a Sherman tank compared clutches I had on 400 cu in V-8s. This the largest, heaviest duty clutch I have ever seen. Looks like it would outlast the engine and maybe even me!
I also noticed that it seems have two halves, front and back, that come apart with just bolts. There are bolts on both sides. I am guessing it is user repairable, although I do not know how or what you would refill it with. I seem to recall hearing it is silicone fluid inside these clutches. Anyway, from the looks of this beast it should outlast me.
Regards,
Mike
1985 Jeep Cherokee Pioneer, 2WD, retrofitted with SD-22 & 5 spd manual trans, a 4X4 Gas Wagoneer ltd. (XJ) Jeep, 4.0 L w/ AW4 auto, and now 2 spare 2wd Jeeps, 87 & 89.
Yeah, its a silicone fluid in there. My Napa right here sells it, they have a few vararites, one thin, one medium, one thick. Sold in little 3 ounce bottles, for something like 6.99 a bottle, kinda expensive.
Try your FLAPS, if you cant get it there I know Toyota dealerships sell their silicone fluid, same stuff, might cost more though.
Word of advice, I reccomend not getting the thicker one, or the heavy duty one. I filled mine with the medium viscosity fluid , and its running just like I would like it, it does spool up when its hot, but it dosent stress the fan too hard from overspeeding.
I was about to replace my fan and clutch when i came upon this thread and am trying to figure out if what i am hearing is sounds like an electric fan may be the way to go. Is this what you are saying? and if so do you have any idea of what kind and size of fan?
My fan clutch died about 1 month ago. I read through this thread and then tried what Phillip had done and removed the fan all together and gave it a whirl. It was 28 C (82F) that day and I climbed the hill out of town. The temp did actually get above the 12 o'clock position on the gauge and once I got to the top it went back to where it normally operates. I did notice that the truck did have a bit more oomph. I checked with Nissan and they wanted $375.00+ for one. I went to my Auto Parts Plus store and they listed one for an 85 720 with an SD25 so I got it for $75.00. The rolling resistance is considerably less at ambient than the OE one was, and will actually "coast" a full turn or two when given a "flip". Once the engine has been run and there is a bit of heat in it then it will coast a bit further. The OE one would not, and might coast the distance of one blade at the very most and that was it. Once removed there was noticable difference between the old and the new just rotating them while holding in your hand. I have installed it and it works perfectly. I have only heard the fan "roar" (lock up) once since I have installed it and it was a 32C (90F) day and I was pulling the hill out of town with 40 2X4's and 5 sheets of drywall on board. The temp got to just above the 12 O'clock position and that is about when I heard it. Approx 1 mile after I crested the hill the roaring stopped. There is no roaring at cold, but it has not been all that cold here (approx 8 C is the coldest one morning). The box the clutch came in has "The Cooling Depot" on it and the model number is 11136924. As there was no 1987 D21 SD25 listed for application (surprise surprise) I assume then that this is a US supplier. I really believe that my mileage has increased as well
Paul
Retired Pauly
Problem with being retired is that you never get a day off.
1987 D21-J SD25 KC
KJLGD21FN
I am getting SOOOOOOOOO tempted to remove my fan:-) It works, but 'roars' for over two miles. And if I shut off for even a few minutes, it roars again for at least half a mile after I take off...
N_R
The old 'six gun' was as popular as the cell phone in its time and just as annoying when it went off in the Theater.
Well I have my fan off right now but it doesn't seem like leaving it off is a long term fix. And i am having a hell of a time finding info on what kind of electric fan i can put in. being limited by space between water pump and radiator, flex a lite told me that they didn't have anything big enough for me. Does anyone have any idea how much CFM this little diesel really needs???
You might consider putting in TWO fans in a side by side configuration... That would avoid having something right where the waterpump hub wants to reside.
N_R
The old 'six gun' was as popular as the cell phone in its time and just as annoying when it went off in the Theater.
well i just picked up a 12 inch fan from Kragen with thermostat and an AC switch. the box says that it will work for a 2 liter gasser, so im thinking that it should do the trick with my 2.5; i will be making some mounts for it and while doing so i figure i will make them so i can move the fan over to one side and add another fan if need arises. we'll see...
