alternator decoupler or Just a worn belt?

mikey1273 · **Posted:** Sat Jun 15, 2013 11:54 pm

I been hearing a squeaky almost chirping sound that to me sounds like a belt or pulley noise but I'm not sure if it could be the dreaded alternator decoupler going bad. the noise is near inaudible at idle but as you press on the throttle it becomes louder. wondering how to tell which it is or if it also could be the fan clutch. I am at 84,000 miles so not to the timing belt interval yet.

Thanks for any input

BlackLibertyCRD · **Posted:** Sun Jun 16, 2013 1:58 am

If it squeaks very loud when you shut the engine off, it is definitely the alternator decoupler.

DOC4444 · **Posted:** Sun Jun 16, 2013 8:19 am

Standard at this mileage. The other tell-tale is dark red dust in the area of the alternator pulley. At this mileage, it makes the most sense to simply replace the alternator with a rebuilt one from Advance Auto Parts. Easy and economical. Requires special tools to replace just the pulley and it often proves time consuming. Does not cost that much more to replace the whole thing.

DOC

mikey1273 · **Posted:** Sun Jun 16, 2013 10:18 am

well it doesn't squeak loudly when I shut off the engine and I have to look for the red dust. my squeak is not that load but constant with engine speed at anything over idle. I am assuming the the red dust would be the clutch material that burnt up

OK well I will look at the belt and all again then check on getting an alternator from advance or auto zome

papaindigo · **Posted:** Sun Jun 16, 2013 10:33 am

At idle look down the serp belt at the tensioner, low on passenger side, is tensioner bouncing or barely twitching. If the former your alternator pulley is likely shot.

mikey1273 · **Posted:** Sun Jun 16, 2013 1:16 pm

there is no red dust around the alternator but the belt seems like it has more give when I push on it than what I think is normal for belts on cars I owned in the past... none used a singe serpentine though. The tension-er seemed to have a little twitch to it but not really noticeable until I put the A/C on. Maybe I will just try a belt first.

papaindigo · **Posted:** Sun Jun 16, 2013 2:46 pm

There was a recent chat about a noise from that area that was thought to be the AC clutch but it turned out to be the alternator clutch. IIRC when the AC clutch engages it puts an added load on the belt and the alternator tensioner. If I'm reading you correctly the serp belt tensioner is essentially steady with the AC off but begins to bounce a lot with the AC on. If that's the case I still lean toward cause being alternator clutch.

mikey1273 · **Posted:** Sun Jun 16, 2013 5:00 pm

Yes you read it correct. so looks like I need a new clutch on that or a reman. alternator as well as a new belt. how much risk is there that this is going to cause a breakdown any time soon? I have a camping trip planed for next weekend and with work there is really no way I'm going to have time to do it before. I'm going under 100 miles away but will be towing a 1200 pound pop up. other than the noise which I cant hear at full driving speed its running great.

papaindigo · **Posted:** Sun Jun 16, 2013 8:36 pm

If it is the alternator clutch then driving too long, wish I could say how long that is, can trash the serp belt tensioner which is pricey. 100 miles shouldn't be problem but... kind of depends on how long the problem has been going on.

CATCRD · **Posted:** Sun Jun 16, 2013 9:05 pm

Thing is, that the decoupler is not really used at anything much over idle speed. Once you are above idle, you're above the resonance zone that the decoupler is designed to compensate for. It's not active as you're cruising down the highway because the frequency of impulses from the pistons are way above where the belt resonates. Makes me think it's not your pulley if you can heart it at full speed.

MedicPatriot · **Posted:** Sun Jun 16, 2013 10:29 pm

My symptoms were similar, except my noises were at idle and WENT AWAY with higher RPM's. The A/C make the noise very loud, but went away at higher RPM's.

Replaced alternator and problems solved.

mikey1273 · **Posted:** Sun Jun 16, 2013 11:28 pm

well it does not go away when I'm driving through my neighborhood with the windows down I can hear it. I did dive a few miles on the interstate tonight and could hear it a little with the window down. mine can't be heard at idle but I hear it when I hit the go pedal aka gas.

I started hearing it a few days ago and my first thought was oh I must need a new belt so I go one and have been carting arount it but have not got to put it on yet.

at this point I don't care about trashing the belt it has probably been on since day one and a new one was like $25

mikey1273 · **Posted:** Mon Jun 24, 2013 7:10 pm

Well I was able to get a real mechanic to look at it today after I took it camping and pulled my camper 100 up and came home over the weekend. He says and showed me it is the tensioner. The pulley isn't even runningstraight any more it could break any day. We called a few parts places they had no listimg for the part of course. We called Jeep dealers. He called one I called the other. He was told $285 & on back order for 1 month. I was told by the other dealer the tensioner was $275 with 50 on back order and 20 units in production. So I looked up IDparts.com. found it for $156 called and asked about the shipping time to Pennsylvania. 2 days and its instock. The part is a genuine VM part. Its good someone is doing a better job supporting us than Chrysler is.

Hexus · **Posted:** Tue Jun 25, 2013 10:15 am

I was a bit of a naysayer at first, but I'm a huge IDParts fan now, I even sport their sticker on my back window!

Corey is a cool dude in my and many others here's books.

mikey1273 · **Posted:** Tue Jun 25, 2013 6:12 pm

I talked to mike when I called. He was quick and helpful. I did order online since he said it was faster for both of us. The part is now with ups in philly last I checked so yeah way better than the stealer could offer I think they won a new fan here.

Big Montana · **Posted:** Tue Jun 25, 2013 6:27 pm

mikey1273 wrote:

Well I was able to get a real mechanic to look at it today after I took it camping and pulled my camper 100 up and came home over the weekend. He says and showed me it is the tensioner. The pulley isn't even runningstraight any more it could break any day. We called a few parts places they had no listimg for the part of course. We called Jeep dealers. He called one I called the other. He was told $285 & on back order for 1 month. I was told by the other dealer the tensioner was $275 with 50 on back order and 20 units in production. So I looked up IDparts.com. found it for $156 called and asked about the shipping time to Pennsylvania. 2 days and its instock. The part is a genuine VM part. Its good someone is doing a better job supporting us than Chrysler is.

Good God, what a bunch of jerks. I'm so tired of hearing stories about these prices. I'll be looking into ID Parts for sure.

mikey1273 · **Posted:** Thu Jun 27, 2013 2:30 pm

Big Montana wrote:

mikey1273 wrote:

Well I was able to get a real mechanic to look at it today after I took it camping and pulled my camper 100 up and came home over the weekend. He says and showed me it is the tensioner. The pulley isn't even runningstraight any more it could break any day. We called a few parts places they had no listimg for the part of course. We called Jeep dealers. He called one I called the other. He was told $285 & on back order for 1 month. I was told by the other dealer the tensioner was $275 with 50 on back order and 20 units in production. So I looked up IDparts.com. found it for $156 called and asked about the shipping time to Pennsylvania. 2 days and its instock. The part is a genuine VM part. Its good someone is doing a better job supporting us than Chrysler is.

Good God, what a bunch of jerks. I'm so tired of hearing stories about these prices. I'll be looking into ID Parts for sure.

I know it's terrible how Chrysler treats us CRD owners and price gouges us. I know here diesel parts are often more but $275 for that at the dealer is insane. realize the list price for the same part on a gasser is $117 and it can be had as an aftermarket part for about $50 I'm sure at rock auto. For an OEM part IDparts is priced more fairly for an OEM diesel part.

black dog · **Joined:** Sat Dec 27, 2008 11:31 pm **Posts:** 46

Mine is squeaking at idle but gone when you rev it up. It started after i changed the upper coolant hose, the power steering must not have been turning right away cause it didn't work for about 20 seconds after start up. The tensioner is moving at idle. I might throw a belt at it to see if it stops squeaking.

nissanfrontier · **Joined:** Tue Dec 22, 2009 4:09 pm **Posts:** 145

I just replaced mine put new goodyear alt clutch pulley on $70. Went back to denso alt so alignment will stay same. No more jumping tensioner for now.

alternator decoupler or Just a worn belt?

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