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Discussion Starter #1
Looks like my idler pulley vibrates back and forth about 1/4 inch? What does that mean? (I think I know).

Jeff
 

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This is on the AC-alt serpentine belt right?

There are a few possibilities: something off on the belt, worn serp belt tensioner, bad AC pulley clutch. After you take the belt off, try sticking a stick in the alternator fan inside it. The pulley should only turn 1 way, if both ways pulley is bad.
 

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Discussion Starter #3
Yes, the serp belt. Where is the a/c fan?

I only hear the noise at about idle rpm, in gear adle 850 rpm or in nuetral at 850 rpm.

It looks like the whole tensioner pulley assembly is vibrating back and forth. The idler pulley is causing the belt to vibrate back and forth where it rolls across the tensioner pulley.

For sure the tensioner pulley or check a/c fan?

Jeff
 

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Discussion Starter #4
Update: replaced the whole tensioner assembly and the new one vibrates just as much. How do I check the a/c fan?

Jeff
 

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I'm sorry, I mistyped. I mean alternator fan, not AC fan, whoopsie! The alternator fan is inside the alternator. By counterholding it, you can rotate the alternator pulley, it should only turn 1 direction.
 

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Discussion Starter #7
If it is the alt fan, do i need to replace alternator?

What is counter hold?

I really appreciate your help!

Jeff
 

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Sorry, let me describe it more. There's a fan inside the alternator to cool it. It is attached to the shaft inside. The pulley is also attached to the shaft but it has a one way clutch on it. By holding the fan with a stick , you can test the pulley by turning it both ways. It should only rotate 1 way. Any play in other direction = bad pulley. You can replace it by loosening the bolt in the middle but you need a special tool, can buy it from metalnerd.com.

I can't say if it's wise to drive it, that would have to be your judgement call...but they normally don't fail suddenly...except when they do!
 

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Discussion Starter #11
Does it make sense to you that the tensioner assembly would vibrate if there were a problem with the alt fan clutch pulley?

I can see the fan but need to clarify. IS there only one pully, the one driven by the belt? And would I be replacing that pulley only?

Jeff
 

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Yes. A vibrating tensioner is sometimes caused by a bad alt pulley so it's worth checking. Vibration could be caused by something else on the belt too. There is only 1 pulley on the alternator.
 

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Discussion Starter #13
basically at the same time turn one side clockwise and the other in the opposite direction.
Sorry to bug, but one side of what?

Do you mean one side of the alt fan vs the other side of the alt fan? Or , on the other hand, one side being the alt fan and one side being the alt pulley?

Also, the belt wobble is worse with the compressor on. Also, the compressor is making noise when I first cut it on.

How do I replace the a/c compressor clutch?

Jeff
 

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Sorry to bug, but one side of what?

Do you mean one side of the alt fan vs the other side of the alt fan? Or , on the other hand, one side being the alt fan and one side being the alt pulley?

Also, the belt wobble is worse with the compressor on. Also, the compressor is making noise when I first cut it on.

How do I replace the a/c compressor clutch?

Jeff

this one : one side of the alt fan vs the other side of the alt fan
 
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