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TESTING FAN CLUTCH

tgregg

tgregg

NAXJA Member #1444
Location
Oak Hills, CA top of Cajon Pass
How do you test the fan clutch? I pulled my boat home from the lake today (2000 ft grade climb) and pegged the temp gauge. My electric fan is running, new thermostat (195), and new water pump.
I really don't drive the XJ much (I have a motorcycle) but I need it to be able to pull the boat. Can I eliminate the fan clutch with a solid spacer? If so any body know of a source?
 
Hey there

Yeah I had a similar problem with my xj, deff. sounds like the clutch fan to me. ya realy dont need a spacer for the fan, either put a new one in or just rip it off of there, drill a couple of holes through the front of the clutch near the temp spring, run a couple of grade 8 bolts through there and put a nut on the other side, slap it back in. I did this on my xj, sounds like a semi comming down the road (which is kinda cool) and it does suck up a bit of power but boy oh boy does it keep the engine cool. I never get above 200 degrees and I live out here in vegas where we frequent 110-115 degrees easy.
well I hope this helps some :) best of luck!!!!!

P.S. if ya wanna test the fan clutch, get the engine up to opperating temp, turn the engine off, give the fan a spin with your hand, there should be some resistance, note the fan should not freewheel.
 
If you have an automatic tranny, anytime you are towing and not driving on flat roads you should use the 3 position on the shifter, not the OD (overdrive) position. OD generates extra heat on hills and passes. You should also install a tranny cooler if you don't have one now.
 
Tim_MN said:
If you have an automatic tranny, anytime you are towing and not driving on flat roads you should use the 3 position on the shifter, not the OD (overdrive) position. OD generates extra heat on hills and passes. You should also install a tranny cooler if you don't have one now.
Click to expand...

Thanks, Actually I was in second coming up the steep part, I never tow in OD.
My A/C doesn't work and I'm thinking of pulling the A/C condenser off and putting a trans cooler there. My experience though with a tranny cooler is it makes the engine run even hotter. The grade I climb is only about 5 miles but it really get's HOT fast!
I like the bolt through the clutch idea...yea CHEAP, a man after my own heart.
 
Get the engine to operating temp and stick a roll of newspaper in it---don't lose any fingers. If it shreads the paper its fine and if the fan stops it needs to be replaced.
 
if/when you bolt through the clutch, keep a close eye on it because i discovered that the clutch wore down to the point that the fan was able to wobble and at various RPMs, would contact the shroud, which suggests that eventually it could wear to the point it might contact the radiator and that would be bad, mkay?
 
There are different fan clutches out there for heavy duty applications. I believe they will rotate the fan at a certain percentage of engine rotation, regardless of temperature. That'd be a safer approach than bolting the fan clutch. At higher RPM's and stuff I don't know if I'd trust the fan. Also I'm sure it'd bog you way down. And if anything contacted it, there'd be no clutch to allow slippage.
 
Jess said:
Get the engine to operating temp and stick a roll of newspaper in it---don't lose any fingers. If it shreads the paper its fine and if the fan stops it needs to be replaced.
Click to expand...


Great idea!!!! NOT!!!

Doing that bends up your fan blades which will cause premature wear to your fan clutch and waterpump because of the imbalance.
 
My fan is on a seperate pully; not on the water pump. With the I6 anyway, which I assume he has if he's towing a boat.

The 4 cylinders might be different as they have the fan in the center and no electric fan.
 
I don't remember where I picked up this bit of info on testing the fan clutch and I'm not sure if it applies to all models:

To check the clutch fan, disconnect the bi-metal spring and rotate it 90° counterclockwise. This disables the temperature-controlled, free-wheeling feature and the clutch performs like a conventional fan. If this cures the overheating condition, replace the clutch fan.
Click to expand...
 
Yeah, I've heard of that "test" before too. Although it doesn't make too much sense to me;

A) I'd think you'd want to tighten the spring to cause less freewheeling.

B) It'd still freewheel, wouldn't it?
 
On my 4.0 it is a PIA to get the clutch off but it seems to me that heavy duty option might be a good way to go. I'll check that out. This baby has 220k on it and the fan clutch looks original.
 
Some suggest replacement every 5 years. There is no good way to test it. More often than not, overheating is related to the fan clutch if you do not replace it on a regular basis. Do a search.
 
Hi,
My 93 XJ 4.0 AW4 was overheating like yours even without pulling a boat, any long climb or running the a/c would start it overheating. I changed the waterpump as it was leaking and also fitted a new radiator, while I was doing this I locked up the fan clutch with 2 bolts. It does not overheat anymore! There is a bit more noise from the fan but not enough to worry about and no noticeable difference in power. I can run all day at 80 mph now, no problem, run the a/c all day, no problem. It would probably have been OK without locking the fan but I feel safer knowing it will not overheat, no matter what.
 
A heavy duty usage fan clutch would probably be safer though, in my opinion. Although apparently there haven't been any problems yet with running some bolts through the fan clutch.....personally I'd rather not take a chance! Something spinning at a possible RPM of 5000+ without any slipping being allowed doesn't ease my mind for some reason.
 
i didn't feel like reading the other comments, so i don't know if this has been said or not. turn the little spring on the front of the fan clutch 90degrees counterclockwise. if the temps stays normal at that point, then the clutch is bad and needs to be replaced. (from factory service manual)
 
Jeepcreep said:
I locked up the fan clutch with 2 bolts. It does not overheat anymore! I feel safer knowing it will not overheat, no matter what.
Click to expand...
don't kid yourself, there are still many other components in the cooling system that can fail causing you to overheat. particularly, the radiator, if it becomes clogged, it will not cool efficiently, regardless of how much air flow you force through it, that's where i am on my rig now...
 
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