fan clutch slow or fast spinning?
CF Veteran
Joined: Mar 2010
Posts: 47,923
Likes: 38
From: Broward County Fl.
Year: 1989 xj sport 2dr
Model: Cherokee
Engine: 12 hole bosch Injectors
I read confusing things on this, and would like to use your know-how.
The fan clutch on the XJ (97 in my case):
Should it have (significant) resistance when cold or hot?
Some say resistance when cold and less when hot (which it does in my case, no overheating issues when standing or freeway, btw)
But I also read the other way round.
I know it contains a viscous material, and I guess that when this heats up it should become more ' flowy', therefore less resistance when hot!?
Would greatly appreciate your insight on this, since I would like stay ahead of overheating issues in the future by diagnosing problems with the fan clutch early.
Thanks in advance!
The fan clutch on the XJ (97 in my case):
Should it have (significant) resistance when cold or hot?
Some say resistance when cold and less when hot (which it does in my case, no overheating issues when standing or freeway, btw)
But I also read the other way round.
I know it contains a viscous material, and I guess that when this heats up it should become more ' flowy', therefore less resistance when hot!?
Would greatly appreciate your insight on this, since I would like stay ahead of overheating issues in the future by diagnosing problems with the fan clutch early.
Thanks in advance!
Senior Member
Joined: Mar 2011
Posts: 651
Likes: 0
From: Norway
Year: 1993
Model: Grand Cherokee
Engine: 4.0L I6
If the fan cluch are new/good you will heare it realy loud when starting a cold engine, after going 500-1000 meters it would be silent, when it gets hot you should hear it again.
On a cold engine the clutch is hard to spinn, its need a litle "work" to get loose, the oil inside it has to get warm to let it spinn free. When the fan clutch get hot one part of it increases and then it "grab" into the other part. So on a normal temperatur it should be realy easy to spin.
On a cold engine the clutch is hard to spinn, its need a litle "work" to get loose, the oil inside it has to get warm to let it spinn free. When the fan clutch get hot one part of it increases and then it "grab" into the other part. So on a normal temperatur it should be realy easy to spin.
Last edited by pwb; Apr 14, 2012 at 04:17 AM.
CF Veteran
Joined: Mar 2010
Posts: 47,923
Likes: 38
From: Broward County Fl.
Year: 1989 xj sport 2dr
Model: Cherokee
Engine: 12 hole bosch Injectors
If the fan cluch are new/good you will heare it realy loud when starting a cold engine, after going 500-1000 meters it would be silent, when it gets hot you should hear it again.
On a cold engine the clutch is hard to spinn, its need a litle "work" to get loose, the oil inside it has to get warm to let it spinn free. When the fan clutch get hot one part of it increases and then it "grab" into the other part. So on a normal temperatur it should be realy easy to spin.
On a cold engine the clutch is hard to spinn, its need a litle "work" to get loose, the oil inside it has to get warm to let it spinn free. When the fan clutch get hot one part of it increases and then it "grab" into the other part. So on a normal temperatur it should be realy easy to spin.
Thread Starter
CF Veteran
Joined: Jan 2012
Posts: 3,170
Likes: 312
From: Australia
Year: 1997 (RHD)
Model: Cherokee (XJ)
Engine: 4.0 ltr
If the fan cluch are new/good you will heare it realy loud when starting a cold engine, after going 500-1000 meters it would be silent, when it gets hot you should hear it again.
On a cold engine the clutch is hard to spinn, its need a litle "work" to get loose, the oil inside it has to get warm to let it spinn free. When the fan clutch get hot one part of it increases and then it "grab" into the other part. So on a normal temperatur it should be realy easy to spin.
On a cold engine the clutch is hard to spinn, its need a litle "work" to get loose, the oil inside it has to get warm to let it spinn free. When the fan clutch get hot one part of it increases and then it "grab" into the other part. So on a normal temperatur it should be realy easy to spin.
So this is exactly the other way round!
difficult when cold, easier when hot!
You see the confusion here...
CF Veteran
Joined: Mar 2010
Posts: 47,923
Likes: 38
From: Broward County Fl.
Year: 1989 xj sport 2dr
Model: Cherokee
Engine: 12 hole bosch Injectors
Senior Member
Joined: Mar 2011
Posts: 651
Likes: 0
From: Norway
Year: 1993
Model: Grand Cherokee
Engine: 4.0L I6
Senior Member
Joined: Mar 2011
Posts: 651
Likes: 0
From: Norway
Year: 1993
Model: Grand Cherokee
Engine: 4.0L I6
Inside there is some oil, this oil is like all other oil thik when cold. When it warms up after driving 500-1000 meters it get so warm that the clutch spinn easy. When one part og the clutch get hot (the front) the litle "rings" inside grab the other part and its hard to spinn. If you look at the front of the clutch there is a metal spring there that change shape/expand when it get warm, i think that one then pushes the disc with the rings down so it grabs the part that screwed to the water pump.
Thread Starter
CF Veteran
Joined: Jan 2012
Posts: 3,170
Likes: 312
From: Australia
Year: 1997 (RHD)
Model: Cherokee (XJ)
Engine: 4.0 ltr
Inside there is some oil, this oil is like all other oil thik when cold. When it warms up after driving 500-1000 meters it get so warm that the clutch spinn easy. When one part og the clutch get hot (the front) the litle "rings" inside grab the other part and its hard to spinn. If you look at the front of the clutch there is a metal spring there that change shape/expand when it get warm, i think that one then pushes the disc with the rings down so it grabs the part that screwed to the water pump.
Thanks. Great pics and I'm glad that I started this thread in some way, because as it turns out there are different 'dimensions' to the "easyness" how the clutch should spin: difficult- easier- more difficult when cold - warm - hot.
Thanks all!
CF Veteran
Joined: Nov 2009
Posts: 8,172
Likes: 17
From: The Republic of TEXAS
Year: 1998
Model: Cherokee
Engine: 4.0L HO
Spin testing the fan is not reliable and the factory test procedure is somewhat drawn out. The XJ uses a thermal fan, not a non-thermal. Fan clutch performance slowly degrades with time/miles. If u don't know how old it is, just replace it (+/-$35). We tried a larger than stock clutch on our XJ......constant noise which also means constant extra load on the motor.....went back with stock type clutch.
Last edited by djb383; Apr 14, 2012 at 08:52 AM.
Thread Starter
CF Veteran
Joined: Jan 2012
Posts: 3,170
Likes: 312
From: Australia
Year: 1997 (RHD)
Model: Cherokee (XJ)
Engine: 4.0 ltr
Unfortunately, every single part of a Jeep here in Oz, costs about 4-6 x what you guys in the US pay for it, wether it be a big or small item. Yes, also if shipped.
Trust me, many many times, I wish I could afford changing the parts as easy as you guys...
Trust me, many many times, I wish I could afford changing the parts as easy as you guys...
Last edited by Roler; Apr 14, 2012 at 09:02 AM.
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