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Discussion Starter · #1 ·
I experienced a squealing sound upon start up and stays until everything gets good and hot coming from the front that seemed to me to be at the serpentine belt / idler pulley. I got with my local off-road mechanic friend and he repacked the bearings to get me by since no one had the idler pulleys in stock. It ran quiet for about a day and then started squealing again.

The parts came in and he replaced the idler pulleys. However, right after installing them, the sound began again. I drove it a day or two just to see if they'd "settle in" i.e. bearings distribute lube etc. (was grasping a little since just put in new parts).

Anyways, we have a new set of idler pulleys coming. Never know...could be faulty parts. I figured I would check on here to see if you all had any other ideas like maybe some adjustment, some other reason for them to be squealing, etc.

Appreciate any help.
 

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Discussion Starter · #3 ·
Well, just heard from my friend that Jeep says to change the bolts too so got them ordered as well. Seems there is some service bulletin about it maybe.
 

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Discussion Starter · #4 ·
See this thread for a discussion. It turned out to be the serpentine belt:

2012 JK idler pulley replacement question - Jeep Wrangler Forum
https://www.wranglerforum.com/f202/2012-jk-idler-pulley-replacement-question-2363945.html

Look to get a ribbed type belt like on post #20 picture and see why it may not be easy to find it.

Hope this helps.
Appreciate this. If nothing else, it would be a bad idea to go ahead and replace the belt (at 60,000 miles now) and if the belt that currently on is in decent shape put it into my tools for emergency parts.
 
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As I mentioned in the thread, low mileage seems to be no guarantee for quietness. At least not to my experiences.

Try to get this ribbed version while you can. It may be an outgoing version (hopefully not).
 

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being a 2013 I would redo all the pullys and your water pump while your at it and flush the cooling system.
 
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Get a listening device (auto stethoscope) and place the tip on each bolt of each of the numerous pulleys you have. If I recall correctly there are about 5 including the idler pulley. The bad bearing in a pulley if bad will definitely show itself through the grinding/squealing sound in the auto stethescope. If one of the pulleys is bad you will hear it for sure that way. I was able to clearly tell which one it was on mine. Unfortunately it ended up being the idler pulley on the belt tensioner itself. I just bought a new tensioner from quadratec (OMIX-ada brand) for about 115$. Installed it and was good to go.
 

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Quick question for the collective here:

When you purchase pullys...some of them come with bearing caps even though they are "sealed" bearings... should these be used? I don't think the stock 3.6 has them on the bearings...

Screen Shot 2019-09-04 at 12.08.47 PM.jpg

<D>
 

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Actually....looks like you don't need to use them on the 3.6 as the factory bolts seem to have that built into them...

 

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I had what you describe and was convinced it was a bad bearing, perhaps in the alternator or elsewhere. Just for kicks, I splashed a little water on the belt with the engine running. The squeal went away until the water dried up and then the squeal came back. Replaced the belt and the squeal is gone for good. I’d try that before more expensive solutions like replacing bearings, pullies, etc.
 

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It sounds like your belt may be dry/cracked, I would replace the belt as your going to remove it to replace the pulleys anyway
 
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