What would it be?

the belt on my motor (3.7L) is bit squeeky, I think its coming from the Alternator pulley, my question is would the Alternator be going bad or the pulley itself?

Try spaying a tiny bit of penetrating oil on the pulley bearings one at a time. Run engine in between each one. Do not spray the belt. I haven't looked on mine yet but today read the alternator pulley may have a clutch within. If not it doesn't have a bearing on the pulley.

sure its not the tensioner going bad or one of those pulleys. would be the first place I would look
putting oil on them will do nothing at all really

Areyou sure it is not the belt itself? even if new...a dab of comet on th ebelt will shut it up if it is the belt

I thought my tensioner pulley bearing was making noise. I sprayed a tiny bit of penetraiting oil on it. The noise went away. I replaced it yesterday with a "Gates" 38009 for $25.00. The box says made in USA. When I opended it the new pulley bearing itself says NSK 6203DG3 CHINA I guess they meant assembled in USA or someone made up some box stickers with a gates name. It did match the old pulley bearing number exactly. Why the penetraiting oil penetrated the bearing seal, eliminated the noise and told me that was the problem I'll leave up to you to figure out. I think it has something to due with friction creates vibration and is transmitted to our ears where our ear drums recieve the vibration and we call that sound or noise.

Yes it could be the tensioner itself or belt or any other moving part at this time. Troubleshoot

tommudd said:

sure its not the tensioner going bad or one of those pulleys. would be the first place I would look
putting oil on them will do nothing at all really

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Sorry I respect you posts and have learned a lot from you regarding the KJ as it is new to me. Food for thought.

I have an accelerometer which I use weekly to troubleshoot and or document vibrations on large super yachts mostly. I have even installed them permanently on many. Every moving part has a given frequency and Gforce of vibration when new and it changes as it ages. We document then monitor vibrations in conjunction with a timed light to determine frequency. When something like a bearing in a motor or on a pulley’s vibration changes we spray you guessed it Penetrating oil on it and watch the accelerometer. Wala We replace it before it causes a problem. I know troubleshooting is a dying thing but you can’t be a parts changer when an engine costs about $750,000.

Once you are approaching 60k miles onwards, and are replacing the EPDM belt, to ensure a long lasting install and headache proof future, get a Dayco complete assembly of the tensioner and idler pulley.
Do it once, do it right. Maybe even have these as spares would be great.
You can remove the belt and spin the alt pulley, and hear/ feel if something is up there.

Dayco?? Ive always read not to use Dayco. Ill probably either go with a Gatorback or Gates. You can get either from Rockauto.

Yes I guess I should have clarified the Dayco tensioner is good but not the belt. Get the Gates Miro-v EPDM belt.
Link in forum:
http://www.jeepkj.com/forum/showthread.php?t=45575&highlight=EPDM

JeepJeepster said:

Dayco?? Ive always read not to use Dayco. Ill probably either go with a Gatorback or Gates. You can get either from Rockauto.

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Same thing I've heard.

get yourself a new tensioner assembly and a new gatorback belt. if you have substantial miles on it these are easy and fairly inexpensive replacement parts. Anymore with the price of tensioner assemblies I am just inclined to replace the whole thing rather than take it apart (even if possible) and replace pulley/bearings.

the gatorback belt if I remember correctly had to be bought based on size and not based on vehicle. I cannot remember, maybe that was my other vehicle, but if you don't see one listed for the liberty just do it by size/ribs.

Believe the gatorback part number is 4060865. At least, thats what I ordered today and no, I couldnt look it up by vehicle. Had to find the belt length and ribs.
$22 after shipping from amazon (dont remember the actual supplier name)
I bought one for another vehicle from Summit racing, but I think I overpayed.