DirtyComanche Posted July 14, 2019 Share Posted July 14, 2019 4.0L related. Everyone who upgrades their mechanical fan does it in one of two ways, either they throw a ZJ clutch on the stock fan, or they go to an electric fan(s). Or at least that's my assumption. Does anyone know if there is a better mechanical fan out there that fits? I don't believe the blade profile ever really changed over the production run of the XJ, and it's not exactly a space aged design. Link to comment Share on other sites More sharing options...
Pete M Posted July 16, 2019 Share Posted July 16, 2019 oooo... good question. that would be a sweet upgrade if such a thing exists. Link to comment Share on other sites More sharing options...
omega_rugal Posted July 16, 2019 Share Posted July 16, 2019 IF such thing exists i won´t be a bolt on upgrade, so why bother? go full electric or put a plastic one like me. if you can have more airflow at least ditch some weight Link to comment Share on other sites More sharing options...
DirtyComanche Posted July 17, 2019 Author Share Posted July 17, 2019 7 hours ago, omega_rugal said: IF such thing exists i won´t be a bolt on upgrade, so why bother? go full electric or put a plastic one like me. if you can have more airflow at least ditch some weight Assuming it couldn't be a bolt on is a bit naive, the fan pulley uses a fairly generic pattern for the hub, and many different fans will fit it. The kicker is you need a reverse rotation fan that's small enough to actually fit in the minimal amount of space available. Full electric is great if your electrical system is working correctly. Experience has shown that temperature switch failures or anomalies seem to be common, which you certainly can address by using an override switch but at the expense of complicating the system. Having to run one fan constantly also adds a significant base load to your electrical system, which may not be an issue assuming you have enough alternator, and that that alternator is working; more than once I have made it home or off the trail with a dead alternator by shutting off everything I could and running the battery down, with an electric fan you would probably get about half the amount of run time versus not. What plastic fan do you have? If the blade profile is more modern then it probably does move more air, or at least isn't producing as much drag to do it. The factory mechanical fan is NOT an efficient profile. Link to comment Share on other sites More sharing options...
omega_rugal Posted July 17, 2019 Share Posted July 17, 2019 38 minutes ago, DirtyComanche said: What plastic fan do you have? beats me, IIRC it came from a dead nissan efan, made some holes in it and coupled to the water pump with a custom flange, pulls as much air as the old mech one but weights lots less, no more overheating problems, finally... if i only put a shroud on it it´ll be more efficient but like i said it has not overheated as it is, and i live in a place where 40 degrees in the shade is considered "normal"... a few weeks ago i had to tow my friends WJ (dead ECU) and after 10 miles or so it began to over heat, first time with the plastic fan, i let it cool and kept going for another 10 miles with no problems... may add an efan for such situations... 38 minutes ago, DirtyComanche said: Assuming it couldn't be a bolt on is a bit naive, the fan pulley uses a fairly generic pattern for the hub, and many different fans will fit it. The kicker is you need a reverse rotation fan that's small enough to actually fit in the minimal amount of space available. the ones that bolt on won't fit, the ones that fit will not bolt and the ones that fit and bolt will rotate backwards so if you find it, please share Quote The factory mechanical fan is NOT an efficient profile. a design leftover from the old 258? Link to comment Share on other sites More sharing options...
Jeep Driver Posted July 17, 2019 Share Posted July 17, 2019 1 hour ago, DirtyComanche said: Assuming it couldn't be a bolt on is a bit naive, the fan pulley uses a fairly generic pattern for the hub, and many different fans will fit it. The kicker is you need a reverse rotation fan that's small enough to actually fit in the minimal amount of space available. Full electric is great if your electrical system is working correctly. Experience has shown that temperature switch failures or anomalies seem to be common, which you certainly can address by using an override switch but at the expense of complicating the system. Having to run one fan constantly also adds a significant base load to your electrical system, which may not be an issue assuming you have enough alternator, and that that alternator is working; more than once I have made it home or off the trail with a dead alternator by shutting off everything I could and running the battery down, with an electric fan you would probably get about half the amount of run time versus not. What plastic fan do you have? If the blade profile is more modern then it probably does move more air, or at least isn't producing as much drag to do it. The factory mechanical fan is NOT an efficient profile. As with any failure you can be left stranded, I'm for Efans. I'd look to diesel fans, small tractor, I'm assuming they pull more air and low RPMs. Link to comment Share on other sites More sharing options...
Ryno Posted July 19, 2019 Share Posted July 19, 2019 I have had a couple Xj owners tell me that that ZJ fan clutch ate in to their radiators when they were trail riding. I haven`t seen that happen myself but I could see how that would happen with it being such a tight fit. Thats something else to keep in mind I guess. I`m always hesitant to go all electric. Mainly because I don`t know what I`m doing when it comes to electrical, but also the mechanical fan is pretty reliable. I mean the one on mine made it 30 years before needing changed(fan clutch that is). I tend to think that changing the current electric fan for 97+ and a good pair of hood louvers helps out a substantial bit as far as airflow is concerned. Link to comment Share on other sites More sharing options...
DirtyComanche Posted July 20, 2019 Author Share Posted July 20, 2019 12 hours ago, Ryno said: I have had a couple Xj owners tell me that that ZJ fan clutch ate in to their radiators when they were trail riding. I haven`t seen that happen myself but I could see how that would happen with it being such a tight fit. Thats something else to keep in mind I guess. Doing more research on the ZJ fan clutch, I don't think I will go that way. The ZJ fan is much larger and heavier. It sounds like with the much smaller XJ fan on it the clutch tends not to disengage at all. Some users have reported increased noise and decreased fuel economy because of this. From a standpoint of economy I think switching to dual electric fans on temperature switches would likely be the best option. From a reliability standpoint I do like keeping the mechanical fan. I am somewhat torn and will do more digging. I guess I could put a HO style thermostat housing on it and that would net me two locations for temperature switches, which could allow for a fairly reasonable control system. Link to comment Share on other sites More sharing options...
Jeep Driver Posted July 20, 2019 Share Posted July 20, 2019 34 minutes ago, DirtyComanche said: I guess I could put a HO style thermostat housing on it It'll cost you $20 to prove me wrong. Link to comment Share on other sites More sharing options...
m2bandit Posted July 20, 2019 Share Posted July 20, 2019 On my XJ I went from stock to 4 electric fans back to Stock aux fan and a taurus fan, then back to the stock fan with a clutch eliminator and aux fan. It keeps my stroker cool all day wheeling hard. The taurus fan was pretty good but took a ton of juice and took a lot of work to fit it well. Over the years I've grown to appreciate the reliability of a mechanical fan on a well maintained cooling system. If I was you I'd get the fan shroud, I don't know why I never see xj's/mj's with fan shrouds but they're always complaining about cooling. get that HO tstat housing and put a 3/8's NPT Pet C0ck (drain C0ck, drain valve) to help with burping. Note: my XJ is a rock crawler only I wouldn't recommend a clutch eliminator on a daily driver, just get a functional fan. Pet C0ck, and drain c0ck are the actual names of the valve... the parts store/hardware store will likely have the same reaction as this forum's censor when you ask about them. Link to comment Share on other sites More sharing options...
Pete M Posted July 21, 2019 Share Posted July 21, 2019 technically I believe they are a draincock and a petcock, both should get past the auto-sensor. Link to comment Share on other sites More sharing options...
DirtyComanche Posted July 21, 2019 Author Share Posted July 21, 2019 On 7/19/2019 at 6:33 PM, Jeep Driver said: It'll cost you $20 to prove me wrong. I can buy them on Amazon for $13. But I need the HO tstat housing, which is probably $20 by the time I get it to my door. 4 hours ago, m2bandit said: On my XJ I went from stock to 4 electric fans back to Stock aux fan and a taurus fan, then back to the stock fan with a clutch eliminator and aux fan. It keeps my stroker cool all day wheeling hard. The taurus fan was pretty good but took a ton of juice and took a lot of work to fit it well. Over the years I've grown to appreciate the reliability of a mechanical fan on a well maintained cooling system. If I was you I'd get the fan shroud, I don't know why I never see xj's/mj's with fan shrouds but they're always complaining about cooling. get that HO tstat housing and put a 3/8's NPT Pet C0ck (drain C0ck, drain valve) to help with burping. Note: my XJ is a rock crawler only I wouldn't recommend a clutch eliminator on a daily driver, just get a functional fan. Pet C0ck, and drain c0ck are the actual names of the valve... the parts store/hardware store will likely have the same reaction as this forum's censor when you ask about them. It has a shroud, plus the new style aux fan on a switch. The fan clutch is likely NFG which was what probably started all of this. Also I realized it had a 12~ PSI rad cap, which wasn't a problem as originally the overflow was plugged and it was still used as a closed system. I converted it to an open system as I didn't have space for the expansion bottle and it already had the correct radiator in it. I now have a new 16 PSI cap (correct for later XJs and closer to what the closed system runs for pressure), waterpump (no fault found in the old one, likely had been done shortly before I purchased it) and tstat (same as the pump, looked new, was even the correct 195 F, but was a cheap one), and the original debate was to order an XJ fan clutch or a ZJ one. I'm range limited with 37s and only 70L of gas, and don't want to lose more fuel economy. Burping it isn't a problem. Of course when I took all of this apart I realized my accessory drive idlers are all shot, and the alternator bearings are pretty terrible at best, plus I really meant to high mount the alternator and eliminate the idlers anyway... That all said, I still really would like to find a better mechanical fan. Link to comment Share on other sites More sharing options...
Salvagedcircuit Posted July 16, 2023 Share Posted July 16, 2023 Yay thread reboot! Did anyone ever discover a potential plastic fan replacement for the mechanical fan? I'm not looking to change the fan clutch, just finding a better geometry fan to improve the mechanical fan performance. I'm not having an overheating problem, just looking for ways to improve. I'm eyeing the dual OEM 10 blade tyc fan upgrade maybe in the future but that's going to require a new alternator, all new wiring etc.. I'm debating doing some research and purchasing a few fans to try and find a suitable replacement to the very simple metal mechanical fan. Would be neat to find a suitable solution. (the attached images are from a ford taurus and a WJ) Link to comment Share on other sites More sharing options...
Pete M Posted July 16, 2023 Share Posted July 16, 2023 because of how short (top to bottom) our radiators are, this might be a challenge. Link to comment Share on other sites More sharing options...
pizzaman09 Posted July 17, 2023 Share Posted July 17, 2023 I've recently replace my clutch with a new replacement and stock fan as well as put in a new thermo switch for the factory e fan, it works perfectly. Good cooling, even while idling for a long time on a hot day. Link to comment Share on other sites More sharing options...
PIKE Posted July 17, 2023 Share Posted July 17, 2023 I have 1997 Grand Cherokee with a 5.2. There is an upgrade that uses a Jeep Liberty fan which is plastic. I actually did the upgrade and am pleased. I have no idea if such a mod exists for our trucks. I did try the ZJ fan clutch and it was very loud. Since then I have a CSF 3 row radiator. I don't think I could use the ZJ clutch if I wanted to now. If I ever need a new radiator I will probably get the Mishimoto. Link to comment Share on other sites More sharing options...
Salvagedcircuit Posted July 17, 2023 Share Posted July 17, 2023 3 hours ago, Pete M said: because of how short (top to bottom) our radiators are, this might be a challenge. This is definitely a challenge. I'm hoping the growing number of hybrid vehicles with peculiar packaged components may lead to a suitable fan. Fingers crossed. The hunt begins Link to comment Share on other sites More sharing options...
Pete M Posted July 17, 2023 Share Posted July 17, 2023 all the modern small cars I'm familiar with have only electric fans. Link to comment Share on other sites More sharing options...
Salvagedcircuit Posted July 17, 2023 Share Posted July 17, 2023 After some late night hunting, It seems like (2) fans might fit into the XJ fan shroud: 2001-2006 BMW 325i / 330i / 525i / 530i fan. Dorman # 621-584. Center bolt ID: 5.9in. OD: 16.535" 1990-2008 nissan xterra / frontier. Nissan NP300 09-2015. 8 blade. Continental FA70560. 7 Blade version: Continental FA72096 / Dorman 620-450. Center bolt ID: 5.25in. OD: 16.06" for 7 blade, 15" for 8 blade. Both have large center openings to allow for an adapting plate. Both have an OD of 16in and less. From my searches, it seems the XJ/MJ fan is 16in diameter. Jeep XJ / MJ fan clutch: Clutch OD: 5.99" Fan Bolt Circle: 3.25" Fan Mount Dia (to engine): 2.62" Jeep ZJ fan clutch: Clutch OD: 6.45" Fan Bolt Circle: 3.25" Fan Mount Dia (to engine): 2.62" Nissan fan clutch: Clutch OD: 5.85" Fan Bolt Circle: 5.27" Fan Mount Dia (to engine): 4.72" I don't have any of these parts on hand to verify. Either should work with a simple aluminum adapter. I'm going to CAD something up and get an estimated weight of the adapter to see if this is all worthwhile. Think of all the efficiency gains! Link to comment Share on other sites More sharing options...
Pete M Posted July 18, 2023 Share Posted July 18, 2023 is the factory clutch going to hold and release as normal with the lighter fan? Link to comment Share on other sites More sharing options...
Salvagedcircuit Posted July 18, 2023 Share Posted July 18, 2023 17 minutes ago, Pete M said: is the factory clutch going to hold and release as normal with the lighter fan? That is a good question. I'm not sure at the moment. However, I am genuinely curious what the inner dimension of the nissan clutch is. It lists the fan Mount Dia (to engine) as 4.72in, but is the 4.72in measured from the inner edge of each neighboring slot? I wonder if that slot geometry is generous enough to adapt to the 4.0L engine side. I think I may grab a used one from ebay and find out. Link to comment Share on other sites More sharing options...
Pete M Posted July 18, 2023 Share Posted July 18, 2023 rather than a new one from a parts store that is returnable? Link to comment Share on other sites More sharing options...
Salvagedcircuit Posted July 18, 2023 Share Posted July 18, 2023 31 minutes ago, Pete M said: rather than a new one from a parts store that is returnable? Stop giving me good ideas Pete! Link to comment Share on other sites More sharing options...
gvthnks Posted July 18, 2023 Share Posted July 18, 2023 10 hours ago, Pete M said: rather than a new one from a parts store that is returnable? 9 hours ago, Salvagedcircuit said: Stop giving me good ideas Pete! Or you could just get good measurements at the store and never have to return it. Link to comment Share on other sites More sharing options...
ThatJeepGuy Posted July 19, 2023 Share Posted July 19, 2023 I'm very intrigued to see the outcome of this. My brother is a bmw nerd and I'm sure I could lean on him for some used parts resources if need be. Link to comment Share on other sites More sharing options...
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