Idler, Tensioner, and Belt

[NavalLacrosse]

2011, 3.6L v6

Currently I'm going through the process of swapping parts in order to stop a squeaking issue my my new belt/alternator.
6 months ago, everything was quiet, but My alternator needed replacement. It was easy enough. After the alternator was replaced (and a new belt installed) There has been a continuous 'chirp chirp chirp' squeaking noise coming from the belt. Before swapping the alternator, there was NO squeak.
 

Anyway, hindsight is 2020. I would have went about this in a different order, but here I am.

 

I removed, then replaced the pulley on the tensioner. (not the whole tensioner, just the pulley) and reinstalled it. The chirping is still really loud.

I'm now replacing the Idler pulley at the top of the engine.

 

Questions 1)

I've removed the Idler from up top (the one that required removing engine mount, and lifting the engine. I'm in the process of buying a new on. I'm pretty sure there is no need to replace these parts, but I'm committed now.  There is a little metal plate with teeth on the back side. Is there a replacement part # for this thing? it's the type of part I'm pretty sure is critical for the pulley, and FCA doesn't make spares. mine isn't broken, but it got bent during removal.

 

Question 2)

Assuming that replacing the two pulleys has nothing to solve my issue, I'm pretty sure the aftermarket Alternator is not aligned and is causing the belt noise. Is there any way to adjust the alternator position to align it with the other pulleys? 

If I cant solve this, does anyone know if there are any Goodyear Gator-back quiet belts that I can swap in the make it quiet?

 

[2late4u]

iv always replaced the whole tensioner when putting on a new belt,as sometimes they lose their strength, yes more expensive but never had a problem by doing this also this was advice handed down by my father,  did the new belt get wet with antifreeze somehow? would assume either a misalignment of the belt to pulleys or loss of tension is the cause for your noise,,,good luck

[John/Horace]

My sequence for a 3.6 engine belt squeak was a little different. Squeaking noise was tensioner pulley and a new belt was installed(because of milage) and squeak gone ; then following year alternator went.

 

The original idler and tensioner bearings seem on the cheap side. If you shake a bearing in your hand you should never hear a rattle, new or old.  Grease was gone and bearings were very dry, internal wear probably so have to change.  Complete tensioner is pricy so I only bought the pulley by itself. 
If the belt looked glazed from slipping I would have bought tensioner assembly.  Idler pulley was changed during alternator job. Awkward to change later, rattled when shaken. 

 

Quality of belt is important I find. Gates Micro V make a lot of OEM belts, it’s my first choice...they are more money. Believe it or not a belt can make a squeak all by itself. Goodyear Gator Back belts have given me problems in the past, I wouldn’t use one. 
 

Alternator mounts in a fixed location against front of engine, should not be any lateral adjustment needed. Also if you spin alternator pulley without a belt; ignore any slight noises the brushes make, completely normal. Clean degreased pulleys helpful when belts replaced.

Edited March 1, 2021 by John/Horace

[NavalLacrosse]

So after replacing the upper idler and the pulley on the tensioner but not the tensioner it's self, the noise remains. 

Here's a link to you tube of the belts spinning away while the car idles. From both the video, and just looking at the belt with my eyes I see no lateral wobble. 

when I spray WD40 on the belt the noise goes away for about 10 minutes then it returns. Once the engine is warm, the noise goes away at idle but any revving above idle makes the squeak return. 

There seems to be a subtle difference when the A/C (?) compressor engages... but I'm thinking that's not the cause.

I'm thinking its worth it to just buy another new belt, maybe the el-cheapo I got is what's causing the noise. I'll check out the Gate Micro V, or just other well ranked belts.

 

Edited March 1, 2021 by NavalLacrosse

[Summer Solstice]

Sounds like a plan. A spare belt is never a bad idea.

[John/Horace]

Nice clip. Sounds like belt chirp. The gates micro V belt almost looks like it has an extra ply when you hold it against other belts.

Oem factory belts need to last out warranty period, so are a slightly premium product.  Awkward job swapping belts out on the 3.6; I always toss my old surpentine belt in with the spare tire on my vehicles. In an emergency a ratty worn squeaky belt is better than no belt. 

[John/Horace]

Belt can squeak and not be riding edge;  plies in carcass can start to break down internally.

 

Tensioner pulley he changed bad/noisy out of the box...,yeah possible. Tensioner spring mechanism weak, maybe but burning rubber smell and very loud squeal not symptoms. 

 

If noises started when alternator was changed; it could be source. Crank pulley sometimes have multiple shims, alternator may have a single washer on the armature shaft shoulder. During reman process (new are major $’s usually) wrong thickness spacer shim or out of spec pulley installed...also possible IMO.  Expensive big amp output unit, not that likely.

 

Water pump I assume is original. Sound not changing with temperature, and no talk of glycol leaks. So pump bearing should be fine for a while.

A/c compressor idler starting to get noisy, another possibility.

[NavalLacrosse]

Thanks everyone for replying. today is a warm day, and i'll be removing the belt and replacing it with a new one after cleaning every pulley with brakleen brake-cleaner and a toothbrush.

I'm 90% sure it's Glycol permeated on the belt+pulleys causing the squeek. 

The car didn't make any noise prior to the alternator change- only afterwards. none of the other pulleys grind or rattle. The AC unit engages and disengages without a noticeable difference in squeek (it can be seen clicking on and off in the video. Quite neat to see, if you're willing to mute the gawd-awful noise my car makes! haha.

Anyway:

Seeing as coolant spilled from the hoses when removing the alternator, it's the most likely cause (and probably what I should have checked first )

I'll make the swap and report back. Thanks for going on this wacky Journey with me (pun intended, without shame!)

[NavalLacrosse]

Fixed. :D

Replaced the belt, cleared the pulleys with Brakleen.

back to silent operation.

next: to fix the weak weak weak brakes. (probably a tiny bubble of air in the lines.)