Clipping or chirping or chattering sound from under hood

[The Yin]

I've got a sound that I'm sure is somehow related to something in contact with the driver belt. What? I'm not sure. It's a clipping or chirping or chattering sound (sorry, no video yet.)
Today I was able to make the sound Start or Stop by turning On or Off my AC. Other times it seems to start when I turn the wheel, but stop when I'm not turning.
Power steering and AC work fine. I haven't tested to see what voltage I'm getting to the battery when the truck is on, so I don't know if it could be the alternator. The water pump was just replace a year ago.
The sound comes and goes, it's not constantly there when the engine is running, so I don't think it's a idler of any kind.
Everything seems to work fine, AC, PS, engine temp is good, haven't had problems with it starting, so I'm assuming the Alt is charging the battery.

Are there any particular parts the would make an intermittent sound like that when they are failing?

 

[08TxRunner]

Idler pulleys and tensioner pulley more than likely. Not unusual for the A/C to make it worse since it adds load to the belt. There's a good Gates kit on Rockauto to replace them all.

 

[Inv4drZm]

Mine has a chirping noise that comes and goes, but its from the AC blower motor. Turning the motor up makes it chirp faster, turning it off completely kills it.

But I could see where it could be from a pulley as well.

 

[The Yin]

idler test?

All the idlers should spin freely right?
I might just pop the belt off and spin them to see if any feel restricted.

 

[Bullit_Sponge]

Could also be the belt itself. You don't say when it was last changed, but it does make noise with various accessories engaged, AC, power steering (when turning). You could try a belt conditioner but if it looks cracked I would replace it asap.

 

[The Yin]

Just checked my Rockauto orders, the belt was replaced just over 2 years ago, maybe 25k miles on it.

And now that I think about it, there was an idler that wasn't spinning as well as the others when I replaced the belt. . . :shrug:

 

[nevada]

I've got a sound that I'm sure is somehow related to something in contact with the driver belt. What? I'm not sure. It's a clipping or chirping or chattering sound (sorry, no video yet.)
Today I was able to make the sound Start or Stop by turning On or Off my AC. Other times it seems to start when I turn the wheel, but stop when I'm not turning.
Power steering and AC work fine. I haven't tested to see what voltage I'm getting to the battery when the truck is on, so I don't know if it could be the alternator. The water pump was just replace a year ago.
The sound comes and goes, it's not constantly there when the engine is running, so I don't think it's a idler of any kind.
Everything seems to work fine, AC, PS, engine temp is good, haven't had problems with it starting, so I'm assuming the Alt is charging the battery.

Are there any particular parts the would make an intermittent sound like that when they are failing?

how old is the belt? I would guess it just needs replaced. mine was doing something similar recently. I believe it was the OE belt. 130k on it. a new belt, and all was quiet.

if its a recent belt, then I would suspect the tensioner. when they get old/worn, they cant quite keep enough tension on the belt, and will let them slip a bit. that is the noise you are likely hearing.

 

[MikeinNH67]

And now that I think about it, there was an idler that wasn't spinning as well as the others when I replaced the belt. . . :shrug:

Bingo. Mine is chirping too, pulled the belt and the lowest pulley is not smooth. The rest I pulled awhile back and lubed. The bottom one is a double bearing setup so no way to lube it without pressing the bearings out which is not worth the time.

 

[08TxRunner]

Keep in mind that spinning pulleys by hand is a good way to find a really bad pulley, but it won't necessarily always find a bad one. I've had bad pulleys that seemed fine spinning by hand but were obviously bad when the belt was on.

 

[MikeinNH67]

Bingo. Mine is chirping too, pulled the belt and the lowest pulley is not smooth. The rest I pulled awhile back and lubed. The bottom one is a double bearing setup so no way to lube it without pressing the bearings out which is not worth the time.

Well, this was a fail on my part. I bought 3 idlers in a kit and installed them thinking the bottom one is the noise maker. Nope, noise is still there. I pulled the 4 nuts off the clutch fan as I have had one of these on another vehicle make noise and it's not that. Yes I did put the nuts back on as the pulley would be loose without them. The noise is also there with the A/C on so I'm thinking that is fine. Now I'm contemplating changing the tensioner. You can see it move side to side as the belt spins, makes me wonder if that slight movement is a squeak. That tensioner pulley did not come with the kit.

 

[The Yin]

Hmmm, I think I see which idler is the the problem. I haven't taken anything off to check, but this much movement doesn't seem good.

Click to see video on Flickr.

[/url]idler action [/IMG]

I'll just replace them all anyway. After the 136K+ miles, it might be time.

 

[waypoint]

Well, this was a fail on my part. I bought 3 idlers in a kit and installed them thinking the bottom one is the noise maker. Nope, noise is still there. I pulled the 4 nuts off the clutch fan as I have had one of these on another vehicle make noise and it's not that. Yes I did put the nuts back on as the pulley would be loose without them. The noise is also there with the A/C on so I'm thinking that is fine. Now I'm contemplating changing the tensioner. You can see it move side to side as the belt spins, makes me wonder if that slight movement is a squeak. That tensioner pulley did not come with the kit.

I just posted my experience from last weekend w/ a bad tensioner pulley. NAPA part # 36174, or Gates same part #, fits correctly and fixed my noise. I went nuts swapping in my old spare idlers before I found the tensioner pulley as the squeak/squeal. It had no detectable play, and seemed to rotate smoothly by hand.

 

[MikeinNH67]

I just posted my experience from last weekend w/ a bad tensioner pulley. NAPA part # 36174, or Gates same part #, fits correctly and fixed my noise. I went nuts swapping in my old spare idlers before I found the tensioner pulley as the squeak/squeal. It had no detectable play, and seemed to rotate smoothly by hand.

That's how mine is, seems fine. So you replaced only the pulley itself? I was contemplating replacing the whole unit with the unit below. Thanks for the info!

https://www.amazon.com/Dayco-89371-...087---1--199-&vehicleName=2003+Toyota+4Runner

 

[waypoint]

That's how mine is, seems fine. So you replaced only the pulley itself? I was contemplating replacing the whole unit with the unit below. Thanks for the info!

Yup, just the pulley for this fix. The stethoscope clearly showed the pulley bearings as the noise source, otherwise I'd have replaced the whole tensioner.

Interestingly, the Toyota pulley has two separate bearing assemblies pressed into it. The Gates replacement has only one, longer bearing assembly. Seems to put more bearing surface area than the factory design. Whether the bearing components are same/better/lower quality relative to the Toyota part is unknowable...but the Gates pulley has a lifetime guarantee.

Changing the tensioner is a bear. Have to remove the AC compressor to get to the tensioner bracket. And probably have to remove the alternator to get the AC compressor moved. Unbolting the AC compressor, even with the fan, radiator, alternator, and other front components removed is a PITA.

 

[MikeinNH67]

Yup, just the pulley for this fix. The stethoscope clearly showed the pulley bearings as the noise source, otherwise I'd have replaced the whole tensioner.

Interestingly, the Toyota pulley has two separate bearing assemblies pressed into it. The Gates replacement has only one, longer bearing assembly. Seems to put more bearing surface area than the factory design. Whether the bearing components are same/better/lower quality relative to the Toyota part is unknowable...but the Gates pulley has a lifetime guarantee.

Changing the tensioner is a bear. Have to remove the AC compressor to get to the tensioner bracket. And probably have to remove the alternator to get the AC compressor moved. Unbolting the AC compressor, even with the fan, radiator, alternator, and other front components removed is a PITA.

Yeah, the tensioner looks to be a bear. I didn't notice 2 bearings in that pulley so maybe it's been replaced in the past. I did notice 2 in the lowest one.

 

[waypoint]

Yeah, the tensioner looks to be a bear. I didn't notice 2 bearings in that pulley so maybe it's been replaced in the past. I did notice 2 in the lowest one.

Now that you mention this, my truck was bought used and the pulley I removed last year during the timing chain project may not have been factory. (Have to remove the tensioner pulley to access the water pump bolt behind it.)

The tensioner on it now is an AC Delco part installed during the timing chain replacement, and it has 2 bearings like the #1 lower idler pulley. This tensioner pulley failed after a year and ~30K miles, it's junk. The lifetime warranty via Rock Auto is useless on a weekend when you need the vehicle for work on Monday...lesson learned.

Good luck w/ yours, let us know how it goes.

 

[The Yin]

Not there yet . . .

So I replaced all of the pulleys, even the one on the tensioner. It took longer then it should have cause I kept have to go back and confirm details (location of pulleys and torque). I had my head gasket replaced over a year ago, and they swapped the #1 with the top left #2, so that throw me off as I was part comparing.

Anyway, I got everything back together and it's working. But upon closer inspection I noticed the real issue. My belt tensioner itself is giving out. I watched and could see that the sound would happen when the tensioner was bouncing a little. Seems the spring is just weak after 130k+ miles and 14 years.
Seen here: 20190929_151233.mp4 - Google Drive


At least one pulley (top right #2) had bad bearings, but now I'll be having a mechanic friend replacing the tensioner. I would tackle it myself, but wont have the time before and up coming road trip.

 

[nevada]

So I replaced all of the pulleys, even the one on the tensioner. It took longer then it should have cause I kept have to go back and confirm details (location of pulleys and torque). I had my head gasket replaced over a year ago, and they swapped the #1 with the top left #2, so that throw me off as I was part comparing.

Anyway, I got everything back together and it's working. But upon closer inspection I noticed the real issue. My belt tensioner itself is giving out. I watched and could see that the sound would happen when the tensioner was bouncing a little. Seems the spring is just weak after 130k+ miles and 14 years.
Seen here: 20190929_151233.mp4 - Google Drive


At least one pulley (top right #2) had bad bearings, but now I'll be having a mechanic friend replacing the tensioner. I would tackle it myself, but wont have the time before and up coming road trip.

yep, that is what I suspected.

 

[MikeinNH67]

Mine now seems to be quiet after a new tensioner pulley.

 

[The Yin]

It was indeed the tensioner

Had the tensioner replaced and that took care of it.

For anyone that might have this problem show up, take the time to watch closely if your tensioner is moving at all. I would have IDed this faster if I had.