FAQ: Chirp Chirp Chirp - Belt Squeal, Pulley & Tensioner Squeak

It's a warning that it's about to fail. Consider yourself lucky that you are getting warning noises and it didn't just grenade on you during a long trip.
Replace them all as soon as possible.

mines the SC coupler. from my understanding from Matt...theres no threat if it goes. he checked my idlers and pulleys.

Oh, well that's a different story then.
From what I've read on here you can safely let the coupler go for a while before changing it out.

xxsupergman25xx wrote:

mines the SC coupler. from my understanding from Matt...theres no threat if it goes. he checked my idlers and pulleys.

yes, last time Scotty had his car at my house i (we) checked the belts tensioner and pulleys. the only think i noticed was a worn out s/c coupler. it has quite a bit of play in it, but i dont see it failing any time soon.
now, that's not to say you still wont have a idler sieze up, sometmes you dont get a warning.

In my case, it's the tensioner itself that is chirping, not the tensioner pulley. I changed the coupler and the tensioner kept on chirping. I can take a ratchet and move the tensioner with the engine running and make the noise go away. I believe it's because the spring is wearing out, but it's not going to break off or anything. Mine's been chirping for almost a year now, off and on. I need to replace the tensioner because I've had SC come off a couple times under sharp throttle blips (only once while driving).

EDIT: replaced the tensioner (kept same belt and idler/tensioner pulleys); after 5 months, chirping noise is gone for good.

mine did that too Aaron. i bought a new tensioner for rockauto and it stopped making the noise for about 6 months. now it chirps again, but only when the car is cold. guess i should have opted for the acdelco replacement one

Id say if you hear chirping its belt noise ...
spray a few drops of something ... i used armour all on the inside of the belt , if it goes away ... bingo .
It wouldny hurt to replace the pulleys i bet though either @100k +

Does this sound like the bearings are short in the alternator? It's been chirping for about 400 miles or so but has gotten a little nosier lately. I'm sure it's not the idler because it was changed fairly recently and is no longer the cheap plastic pulley.

If it is, is it possible to just have the pulley/fan or bearing swapped out? I really don't want to shell out the money for the entire alternator if I don't have to.

I couldn't tell from the video. With engine running, try carefully reducing tension to the SC and accessory belt tensioners, using a ratchet. I had a similar chirp - it was the tensioner making the noise.

AA wrote:

I couldn't tell from the video. With engine running, try carefully reducing tension to the SC and accessory belt tensioners, using a ratchet. I had a similar chirp - it was the tensioner making the noise.

Won't the bolt be turning with it running?

No.

If a tensioner pulley bolt is turning, THAT'S where the problem is!

It's damn near impossible for the tensioner bolt to turn. It's reverse threaded so that it can't turn with the engine running. If it were to turn with the engine running, a catastrophic belt failure will quickly follow.

Relieve belt tension by turning the bolt counter-clockwise. It only takes a little movement to reveal the problem. Be careful.

Just relieved tension and noise went away. It did not come back upon releasing the tensioner, but once I revved the engine the noise returned.

FWIW, the tensioner does not move smoothly.

Which tensioner was it? SC or accessory belt?

A write-up for SC tensioner is here: Link. Accessory side will be a little more involved, but similar to swap.

It's the accessory side. I guess since the noise subsided that rules out the alternator.

One quick question, will I need to loosen/remove the ac compressor to swap it out? Just a quick question without looking at the pulley/belt guide.

It doesn't rule out the alternator 100%, but the tensioner moving roughly does suggest it is making the noise, not the alternator. Spin the alternator without the belt, and wobble the pulley to see if any slop. If it's smooth, alternator should be okay.

Check all other accessory and idler pullies as well.

My SC tensioner started chirping around ~160k miles. It lasted a long time before I changed it. It's annoying more than it is dangerous, so you have some time to fix it. Mine always made more nosie in colder, damp weather.

Remove the belt (with engine off) and spin the alternator and other pullies by hand. You should be able to tell which ones are rough.

manofmany wrote:

One quick question, will I need to loosen/remove the ac compressor to swap it out? Just a quick question without looking at the pulley/belt guide.

The accesory belt does go around the A/C comp, but you should not need to remove it. Loosening the belt tensioner removes tension on the entire belt path including the A/C.

Thanks guys!

It got noticeably louder this morning, to the point where I am going to change it immediately. I'm going to pull the belt off to verify the alternator.

Not sure why you never used a stethascope or an old trick, a screw driver with your ear to the handle. Both ways you can pinpoint where the noise is coming from.

I have always shied away from the screwdriver trick. One slip, it gets caught in the belt, and you have a serious problem, or worse. But a true stethoscope, or piece of vacuum hose, these make more sense, imo.

playa wrote:

Not sure why you never used a stethascope or an old trick, a screw driver with your ear to the handle. Both ways you can pinpoint where the noise is coming from.

I actually did use a piece of broomstick and did not hear any noise through it when placed against the alternator pulley.

I removed the belt and the alternator pulley is not exactly sloppy, but does give off an audible chirp-chirp-chirp noise when spun.

I'd say either do some more listening w/engine running, or replace one or both of the parts. Tensioner is about $60, alternator is around $200.

AA wrote:

I'd say either do some more listening w/engine running, or replace one or both of the parts. Tensioner is about $60, alternator is around $200.

if hte tensioner "dances" when the engine is running, the damper is weak and it should be replaced (replacing the pulley on it won't help). If not, and the pulley is binding or squeaking, you could get more life out of the tensioner by replacing it's pulley.

As for the alternator, you could get one from a junkyard that does not squeak without much problem for more like $25 to $40. GM used this alternator on a bunch of cars. If you are gonna get a "new" one get a good remanufactured one, not necessarily a new one. The reman ones will have more robust OE cases and rotors, the rebuilder can put the money into bearings and commutator brushes. I am happy with the Delco reman I got some years ago. Some have complained lately about Delco reman alternators so I'd tell them look at Cardone.

Albertj