Strange chirping/squealing noise

74Ghia · **Joined:** Sun Apr 08, 2012 12:57 am **Posts:** 10

Hello all,

My 2006 Liberty CRD has developed an annoying chirp, squeak noise, I think from the front, serpentine (I hope) belt.

I can't isolate it very well, with the rattle of the engine. It started out very light, and ONLY when the vehicle was put in drive or reverse, once shifted to P or N is was quite again. Now it's quite loud in D or R, and only slight loud in N or P (about like it used to be when it began only in gear). Also, the AC being on seems to make it even louder, especially when it's in gear. There's around 87,000 miles on it now.

Any ideas? To maybe even just begin the process of elimination?

Thanks much...

papaindigo · **Posted:** Sun Jul 14, 2013 1:58 pm

The initial place to look would be the alternator pulley which can get loader when the engine is under load like with the AC running. Check the front of the pulley for lots of red dust and at idle look down the serp belt to the serp belt tensioner which will be bouncing all over the place, not just barely twitching, if that idler pulley is bad. Easiest solution is to get a rebuilt alternator with a lifetime warranty from like AutoZone although the pulley alone can be replaced.

Could also be bad serp belt idler pulleys but to check you need to remove serp belt and spin the pulleys - look for rough or sloppy bearings or grease coming out of the bearings.

74Ghia · **Joined:** Sun Apr 08, 2012 12:57 am **Posts:** 10

I forgot to mention and it might be important, the belt is running smoothly, no bouncing orshaking just nice and smooth. Also, the noise goes away by just raising the idle speed even 100 RPM.

CATCRD · **Posted:** Sun Jul 14, 2013 11:15 pm

74Ghia wrote:

I forgot to mention and it might be important, the belt is running smoothly, no bouncing orshaking just nice and smooth. Also, the noise goes away by just raising the idle speed even 100 RPM.

Yes, your alternator pulley is bad. I think papaindigo mis-wrote idler pulley, but it is the actual pulley on the alternator itself. It's a special pulley with a one way clutch in it. You are about the tenth person this year, it seems like, to have this problem. Your best bet is a new alternator, but the pulley can be replaced separately.

HER_CRD · **Posted:** Mon Jul 15, 2013 6:21 pm

The woman's Liberty here may have the same issue. Noticed it has a chirp that seems to go vary with being in gear and A/C on or off.

ebbnflow · **Posted:** Mon Jul 15, 2013 10:17 pm

If it's worse with AC on, it is most likely your alternator. Don't let it go too long or you will ruin your serp belt tensioner.

geordi · **Posted:** Tue Jul 16, 2013 7:13 pm

Quick idiot proof test:

Idle the engine, verify that the chirp is present. If the engine needs to be warm, then get it to temperature. Basically get it to a point that you know the problem can be duplicated.

Stop the engine, spray behind / into the CENTER of the alternator pulley in front of the alternator body with some WD40. Hold a paper towel under the pulley to catch any spills, you only want it inside the pulley as much as possible.

Start the engine, the noise should be gone... But will return soon.

The problem is your pulley then. If the noise isn't gone - could be the alternator bearings, but from what you describe, 90% chance that it is the pulley.

HER_CRD · **Posted:** Tue Jul 16, 2013 9:03 pm

Is there a cost advantage to rebuilding the alternator over buying a reman?

geordi · **Posted:** Wed Jul 17, 2013 12:21 am

In theory, the pulley can be replaced separately, and you can retain the rest of the unit which really shouldn't have any degrading parts - it is copper wire spinning in a magnetic field. The problem is that there are bearings and diodes in the casing that CAN degrade.

Will they, if the pulley is bad? I don't think so, but the pulley is $45 or so and you get a new one... Onto an alternator that has eleventy-twenty miles on the rest of it. For $150, you get a lifetime warranty on a new pulley AND a new casing with new stuff inside it from Autozone.

I went with the full unit and didn't have a problem with THAT part of the CRD again.

74Ghia · **Joined:** Sun Apr 08, 2012 12:57 am **Posts:** 10

Hummmmm, scratching head.

I tried the WD40 soak the pully on the alternator, the noise does not go away. Also, there's no "red dust" that I can see there. Really bewildered....

harbrlife · **Posted:** Wed Jul 17, 2013 9:15 pm

Got the same thing happening to mine. Haven't had time to fix. I'm hoping it's idler pulley only. My 05 has 185K miles on it & the chirping/squealing goes AWAY when engine has a load on it.

ebbnflow · **Posted:** Thu Jul 18, 2013 10:52 am

When I pulled the serpentine belt, I could visibly tell the alternator pulley was bad. It had a wobble when I turned it by hand.

74Ghia · **Joined:** Sun Apr 08, 2012 12:57 am **Posts:** 10

Thank you everyone!

Replaced the alternator and the serpentine belt today and the noise is gone.

I was worried when none of the "conditions" (no red dust, no wobble, couldn't get it to stop with WD40 even for a few minutes) existed in my case, but the pulley was clearly shot all the same.

Thanks again, for the benefit of your experience!

DOC4444 · **Posted:** Sun Jul 28, 2013 11:23 am

I just came across this thread. I was going to point out that the decoupler rarely lasts more than 100K miles and that replacing the alternator would have been the thing to try, which you did. Good call!

DOC

geordi · **Posted:** Sun Jul 28, 2013 11:54 am

Glad it fixed it for you.

In my experience with many different vehicles from many different manufacturers... I have only VERY rarely had an alternator last more than 100k miles. I had to change the one on my new (to me) Jetta - that had 245k on it when I bought it. The alternator ate itself about 15k later. Was this the original alternator? I don't know, but I suspect it was killed by a drooling water pump - for reasons that escape me, the alternator is directly under the water pump.

No matter where it is located, the engine bay is a violent and hot place. It amazes me that any electronics survive long in there. Just be glad that the computers don't run windows!

Drewd · **Joined:** Mon Feb 06, 2006 12:24 pm **Posts:** 902

Many rebuilds use less reliable/more cost effective pulley decoupler that doesn't last as long.

I've got 125,000 miles on my original alternator and have replaced decoupler once about 35,000 miles ago.

I'm very impressed by how stout the OEM alternator is. I've never had a alternator last that long. When I hit 200k, I'll probably replace the brushes, bearings/bushings as a preventative measure.

Strange chirping/squealing noise

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