how do i know my fan clutch is bad?
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Joined: Jul 2011
Posts: 2,912
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From: Over here...
Year: 1986
Model: Cherokee
Engine: 2.8
A good clutch should have some resistance when you spin it when the motor is cold. When the motor is hot, the fan should spin freely. Pretty simple to diagnose.
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From: Prescott, Az
Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
Herp Derp Jerp
Joined: Nov 2011
Posts: 18,251
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From: Parham, ON
Year: 1999
Model: Cherokee
Engine: 4.0L OBD-II
Telltale symptom: begins to overheat when sitting still, cools fine when in motion.
Normal operation: Fan clutch gains resistance as it pulls warmer air over it. At higher temperatures it will sound like a roaring fan from a big truck if you rev the engine. If you have an IR thermometer, start gently heating the fan with a torch (don't melt anything!) around 190ish it should make some noise as it pulls more air.
There's a much longer technical test but it would cost you the same as a new fan clutch in terms of time and money invested in the test.
Normal operation: Fan clutch gains resistance as it pulls warmer air over it. At higher temperatures it will sound like a roaring fan from a big truck if you rev the engine. If you have an IR thermometer, start gently heating the fan with a torch (don't melt anything!) around 190ish it should make some noise as it pulls more air.
There's a much longer technical test but it would cost you the same as a new fan clutch in terms of time and money invested in the test.
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Senior Member
Joined: Jul 2012
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From: middleburg fl
Year: 1998
Model: Cherokee
Engine: 4.0
CF Veteran
Joined: Aug 2010
Posts: 8,357
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From: Canton, MI
Year: 1999
Model: Cherokee
Engine: 4.0
I think there's a YouTube vid that shows the use of a rolled up newspaper being used to slow/stop the fan while the engine is running (hot). I guess it works.
CF Veteran
Joined: Sep 2011
Posts: 4,172
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From: Riviera, Texas
Year: 1998 Sport
Model: Cherokee
Engine: 4.0
I am sorry. But I would NEVER recommend putting anything in to the fan while a vehicle is running. Have you ever seen what the fan can do to a hand if it is pulled into it??? I have and it is not a pretty site to see. And this is coming from a guy that has done body pick ups after murders and suicides for a few years. I am just putting this because I would rather spend a few buck and change it then lose a finger of a hand.
CF Veteran
Joined: Nov 2009
Posts: 8,172
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From: The Republic of TEXAS
Year: 1998
Model: Cherokee
Engine: 4.0L HO
How do I know if my fan clutch is bad?........
.....or more like how do I know if my fan clutch is good? I say to myself....self, I just spent $35 for a new fan clutch and I took 15-20 min to put it in. Since it's new, I'm reasonably sure it's good, operating at peak efficiency, I still have all my fingers, I'm not guessing if it should spin more or less when hot or cold and......is it just me, or does it sound like pistons are swappin' holes on that beamer?
.....or more like how do I know if my fan clutch is good? I say to myself....self, I just spent $35 for a new fan clutch and I took 15-20 min to put it in. Since it's new, I'm reasonably sure it's good, operating at peak efficiency, I still have all my fingers, I'm not guessing if it should spin more or less when hot or cold and......is it just me, or does it sound like pistons are swappin' holes on that beamer?