fan clutch
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New User
Joined: Dec 2007
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fan clutch
think i posted my last question in the wrong forum. 96 big bronco--got new fan clutch, stayed on all the time. had guy replace again, still stays on, robs my power and squeals when i step on it too hard. guy says squealing isn't anything he did, but it did not squeal before he replaced fan clutch and a/c stuff. i replaced the belt and a questionable idler pulley. should i try a motorcraft one, electric one, flex fan? i want poer back with no squealing. car never had heating issues even when the fan clutch was bad.
Senior User
Joined: Aug 2007
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The fan will always turn with the eng. There are at lest 4 kinds of fan clutch. Centrifugal and thermal standard duty and heavy duty. Most fan clutches now are a thermal clutch that slips more when cold then hot. You will get more noise with a heavy duty one and more drag.
As for the squealing there might be some contamination on the belt from all the hands that have been on it or you might have a bearing going bad. You can take the belt off and turn all the pulleys by hand and see if any fill stiff or make any noise.
As for the squealing there might be some contamination on the belt from all the hands that have been on it or you might have a bearing going bad. You can take the belt off and turn all the pulleys by hand and see if any fill stiff or make any noise.
Tuned
Joined: Feb 2003
Posts: 355
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From: Oregon
I have the original thermal on my '92 and it still works fine. I've had the rig over 10 years, and I've only heard it kick on a couple of times in extreme heat situations, and it's pretty loud.
Like mrknight said, it'll always turn to some degree. I can tell when mine's locked in 'cuz it sounds like a Cessna revving up for takeoff.
With the engine off (and cold) youshould be able to easily spin the fan by hand. If you have the guts, you can check it with the engine running by stopping the fan with your hand. If it tries to rip your fingers off, then it's locked in. If it's working right, it should stop with minimal finger pressure.
Like mrknight said, it'll always turn to some degree. I can tell when mine's locked in 'cuz it sounds like a Cessna revving up for takeoff.
With the engine off (and cold) youshould be able to easily spin the fan by hand. If you have the guts, you can check it with the engine running by stopping the fan with your hand. If it tries to rip your fingers off, then it's locked in. If it's working right, it should stop with minimal finger pressure.
Posting Guru
Joined: Apr 2006
Posts: 1,274
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1pump,
I hope you mean you hold the fan with the tip of your finger (or a stick) and start the engine. I would not recomend trying to stop the fan once it is going. I did this to my motorhome (GMC) and the guy at the auto store told me the clutch is no good if you can hold it back.
I hope you mean you hold the fan with the tip of your finger (or a stick) and start the engine. I would not recomend trying to stop the fan once it is going. I did this to my motorhome (GMC) and the guy at the auto store told me the clutch is no good if you can hold it back.
Tuned
Joined: Feb 2003
Posts: 355
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From: Oregon
It can vary from rig to rig. On my Ranger, with it's plastic fan, I can CAREFULLY stop the spinning fan with my hand, as long as it isn't engaged. Same with my Bronco. I really wouldn't recommend it for everybody, and I wouldn't recommend it at all for a steel fan.
I disagree with the statement about being able to hold it. I've seen plenty of fan clutches fail both ways; either they lock up permanently, or they don't transmit enough torque to the fan and freewheel too easily. This happened on the BroncoII that I had. It overheated while I was waiting in line for a ferry, and as soon as I lifted the hood I could tell that the fan wasn't spinning hard enough. When I got home a few days later, I checked it against my Ranger (which had the same engine). The failed BII clutch, with the engine off, would rotate around several times when I spun it once with my hand. The Ranger would only make about one rotation. Big difference in resistance. When I started it, I could stop the bad clutch with one finger, like it wasn't attached to anything. I still had to use my whole hand on the Ranger.
I disagree with the statement about being able to hold it. I've seen plenty of fan clutches fail both ways; either they lock up permanently, or they don't transmit enough torque to the fan and freewheel too easily. This happened on the BroncoII that I had. It overheated while I was waiting in line for a ferry, and as soon as I lifted the hood I could tell that the fan wasn't spinning hard enough. When I got home a few days later, I checked it against my Ranger (which had the same engine). The failed BII clutch, with the engine off, would rotate around several times when I spun it once with my hand. The Ranger would only make about one rotation. Big difference in resistance. When I started it, I could stop the bad clutch with one finger, like it wasn't attached to anything. I still had to use my whole hand on the Ranger.
