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Old 03-20-2016, 12:05 AM
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Radiator Fan Clutch Question

I replaced the serpentine belt and I was wondering, theoretically speaking, what would happend if you forgot to remove the wrench from the belt tensioner and then started the engine? The wrench would prevent the fan from spinning and I was just curious if that would damage the clutch.

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Old 03-20-2016, 02:27 AM   #2
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Originally Posted by Offroadin View Post
I replaced the serpentine belt and I was wondering, theoretically speaking, what would happend if you forgot to remove the wrench from the belt tensioner and then started the engine? The wrench would prevent the fan from spinning and I was just curious if that would damage the clutch.
Offroadin,
While I most certainly don't advocate do or, even trying this at home, (or any other place for that matter) I've done this many times. I've taken a towel, wrapped it around my hand and, basically when the engines were idling, I slowly introduce the tips of the fan blades to the wrapped hand and, let that fan hit my heavily wrapped towled hand, 'till basically the fan just stopped and, the engine kept on idling.

Now why would anyone in their right mind do this, you ask? I did it as a test to see if the fan clutch bearing was intact and was the source of a noise I'd been hearing. On normal working fan clutches, this can be done without fear of damage. I don't advocate letting that engine run while you sit there with the fan stopped dead for hours on end. I only did it for about 5-7 seconds or so then, let it take off again, and catch up with the engine RPM.

Is this a practice I do on a regular basis? Nope, not at all. In fact, it's been quite a few years since I've had a need to test a fan clutch bearing.
Scott

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Old 03-20-2016, 08:56 AM   #3
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I have only heard of them either seizing up or free wheeling.
Was your fan clutch bearing noisy?
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Old 03-20-2016, 09:36 AM   #4
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If you think it needs to be replaced, just replace it. They are like $43 and take 30 minutes to swap.
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Old 03-21-2016, 12:36 PM   #5
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I have only heard of them either seizing up or free wheeling.
Was your fan clutch bearing noisy?
crallscars,
If you're asking me this question, no, it was not noisy when I did this test. I was looking for a noise but, this test revealed that the noise was not emanating from the fan clutch bearing. It ended up coming from the idler bearing on the engine I was working on at the time.
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Old 03-21-2016, 02:47 PM   #6
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I had considered doing what you did for the same reason, I had already dropped the belt and turned everything by hand with no luck.

Mine turned out to be the compressor pulley bearing, you had to spin it real fast to hear the noise.
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Old 03-22-2016, 12:55 PM   #7
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If it spins more than 3 times freely, then it may be bad.

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