Serpentine belt squeak

[69427]

Perhaps a silly question, but I'm curious what's happening between the belt and one of the pulleys when a periodic squeak/chirp just appears. One day everything was fine and quiet, and the next day it started squeaking. I assume it's one spot on the belt not being happy with one spot on one of the pulleys because the frequency occurrence of the chirp seems slower than the rotational speed of any of the pulleys, and it's more like the belt spot has to travel the full belt length before the noise happens again.

It's just a minor annoyance, but I just prefer to understand the technical reason why when things are happening under the hood.

Thanks for any clarification.

 

[68/70Vette]

I have a 95 Cadillac Seville. It will sometimes drive quietlessly. Then there will be a big squeak from the serpintine belt system somewhere. I bought a cheap stethoscope from Reilley's.....too cheap. From Summit I can see there are headphone systems with microphone systems to seek out the squeak. In someways I don't mind the squeak...it can just continue as far as I'm concerned. I'm guessing that whatever's causing the squeak will eventually fail and I'll know what to replace.......however my wife drives this car..if the serpentine belt breaks due to a jammed pulley bearing, she won't be able to control the car. For about a $100 you can buy a amplifier with headphones and a acoustic probe to "sniff" out the squeaky pulley. I'm really gunshy about taking the car to the Cadillac dealer. Their labor rates for even simple things are really expensive. The water pump is suspect in my mind. The squeak is often not heard at engine idle. It's not from the PS pump. When I apply gas and accelerate, then I get the squeak. The AC doesn't effect the squeak. I think it's the water pump, the idler pulley or the tension pulley.

TIP: NEVER BUY A FRONT WHEEL DRIVE CAR. The engine sits sideways between the front wheel struts and there is almost no room left to work on the front of the engine.

 

[kwplot34]

i dont know,but when you figure it out, find the one on my chevy diesel. replaced the belt,cleaned all of the pulleys,nothing is loose or worn, but it is there. been like that for about 100k miles now. 136k on the truck.

 

[MYBAD79]

had this belt squeek on my Z28..... changed the belt, fixed it for like a week, then the chirping/squeeking noise returned.... then replaced the tensioner incl pulley which finally fixed it for good.....

 

[mrvette]

Watch the idler/tensioner pulley, see if it's moving a bit at one spot of the belt....I have had brand new serp belts seem to have a stiff spot, probable due to the way it was made....and the idler will move due to belt flex....

 

[SuperBuickGuy]

I'm going through this right now with my H3 (that has 103k miles).
Here's what it is:
water pump
power steering pump
alternator
pulleys

that's the overview - here's the issue with each:

water pump has a low growl, almost like a rod knock, that is caused by the bearing seizing up

power steering pump, another growl/vibration through the steering column like it's low on fluid (also a leak from the tank)

alternator, there's a chirping from the front bearing - it was also my first guess for the knocking

idler pulleys - chirping/rattling because the bearing goes out (cheapest bit of the fix).

all-in-all, about $1000 worth of parts to fix :cussing: You can get all of those part for about 1/3-1/2 that price of you buy chinese (I didn't); but then you deal with quality issues

and while I'm at it, I'll change the clutch for the fan.

 

[DC3]

I've had serpentine belts chirp on two different occasions. Once, as Gene suggested, it was the idler pulley. The other time, the crank pulley was separating from the damper and causing a misalignment.

DC

 

[69427]

I believe the issue is the belt surface or a pulley surface, not anything mechanical. If I give the belt a spritz of this the noise disappears.

 

[MYBAD79]

That looks like a GREAT product ....lol

Seriously, I used that anti slip spray (think it was STP) "belt dressing".... Stopped the noise for a few days.... But ultimately it was a weak tensioner, I tried to chase the issue for a while and replaced the belt.... Used the spray on the old and new belt.... i remember bitching about the Chinese crap replacement belt before I found out it was the tensioner ....LOL

 

[69427]

Well, pulled the belt off and spun a couple pulleys. The tensioner pulley bearing sounds smooth but the idler pulley near the alternator sounds a bit rough. Took the pulley off and it looks like I can just press the bearing out and pop a new one in, assuming I can find one. Next move is to google bearing houses in the KC area.

 

[mrvette]

Well, pulled the belt off and spun a couple pulleys. The tensioner pulley bearing sounds smooth but the idler pulley near the alternator sounds a bit rough. Took the pulley off and it looks like I can just press the bearing out and pop a new one in, assuming I can find one. Next move is to google bearing houses in the KC area.

Eh, call the parts house new idler/bearing like 20 bux, not worth the hassle....


:beer:

 

[Twin_Turbo]

Take some emery cloth to the tensioner, that's most likely the issue. Some of mine have a squeeking noise also and it's from rust spots on the tensioner

 

[69427]

Well, pulled the belt off and spun a couple pulleys. The tensioner pulley bearing sounds smooth but the idler pulley near the alternator sounds a bit rough. Took the pulley off and it looks like I can just press the bearing out and pop a new one in, assuming I can find one. Next move is to google bearing houses in the KC area.

Eh, call the parts house new idler/bearing like 20 bux, not worth the hassle....


:beer:

New idler at local Chevy dealer: $76 and has to be ordered.

New bearing at local bearing supply house: $12 and in stock.

 

[mrvette]

Well, pulled the belt off and spun a couple pulleys. The tensioner pulley bearing sounds smooth but the idler pulley near the alternator sounds a bit rough. Took the pulley off and it looks like I can just press the bearing out and pop a new one in, assuming I can find one. Next move is to google bearing houses in the KC area.

Eh, call the parts house new idler/bearing like 20 bux, not worth the hassle....


:beer:

New idler at local Chevy dealer: $76 and has to be ordered.

New bearing at local bearing supply house: $12 and in stock.

Hey, that works too....but at OReilly's at bottom of the hill I have found all manner of idler/tension pulleys in stock ready to go....:drink::drink:

 

[69427]

Got the new bearing pressed into the pulley and reinstalled on the idler bracket. Looked the belt over, along with the pulleys (the tensioner pulley is plastic, to my surprise) and put everything back together. To my great relief when I started the engine the setup was damn quiet.
I'll confess some curiosity why the noise was usually "chirpy" rather than a continuous squeal given that the bearing swap completely quieted the belt system, and how well the talcum powder temporarily quieted things earlier.

 

[mrvette]

Got the new bearing pressed into the pulley and reinstalled on the idler bracket. Looked the belt over, along with the pulleys (the tensioner pulley is plastic, to my surprise) and put everything back together. To my great relief when I started the engine the setup was damn quiet.
I'll confess some curiosity why the noise was usually "chirpy" rather than a continuous squeal given that the bearing swap completely quieted the belt system, and how well the talcum powder temporarily quieted things earlier.

Not so much with the chirp, Mike, but I replaced TWO pulleys on a truck with a new belt, one was the idler, the other the complete tensioner assy....that cured the squeek, BUT....every time a certain spot on the belt went by, the tensioner would bump and it was when the belt was always in the same position as my eyes acting like a strobe and seeing the pattern of the print on backside of the belt.....but long as it was quiet, I shut the hood and shook the tears outta my eyes for looking at that.....

:crap::goodnight:

 

[69427]

The saga continues......

Well, things went well for a few days. Took a couple short trips on cold days and everything was quiet. Yesterday took a couple hour trip and the noise was back. In fact, about an hour into the trip the noise was loud enough that I was starting to worry if I was going to make it back home without the whole front of the engine coming through the radiator. After I got it home I tried the talcum powder spritz on the belt again to see if it was the belt interface or a bearing, and everything quieted up again. Stuff just isn't making sense to me yet. I pulled the serpentine belt off and manually spun the alternator, the p/s pump, the water pump, and the tensioner pulley and idler pulley. Nothing seemed obviously wrong. In an effort to eliminate the belt as an issue I pulled the belt off my pickup (same 5.3L engine) and put it on the Tahoe (The pickup belt, with 150k miles on it, looked brand new. Not faded and no cracks. Whoever supplied the belts to Chevy in 2005 has my respect.). The "new" belt was quiet on the Tahoe for about a dozen miles and then started squeaking. I used a heater hose as a stethoscope and the noise seems to be coming from the waterpump area. As I mentioned before, the waterpump seemed to turn smoothly so a bearing issue isn't obvious to me. I'm certainly not an expert but I would assume if a waterpump bearing was going out that the bearing would make noise all the time and not be quieted by some talcum powder on the belt.
I am curious about the belt and waterpump pulley interface. Unlike my pickup with electric fans the Tahoe has a mechanical clutch fan. I'm wondering if once the engine gets warmed up and the fan "kicks in" that the pulley load is too much for the belt (if the tension is insufficient due to belt stretch or the tensioner spring going "soft"). I need to figure out a way to increase the belt tension or the belt/pulley grip to try to eliminate the possibility of slippage there to see if that stops the squeak.

Anybody see if I'm missing something obvious here?

Thanks,
Mike

 

[010752]

a periodic squeak/chirp just appears.

That's usually a very early sign that a sealed bearing is starting to go.
Apparently it's gotten worse.

Check to see if your alternator has a one way clutch. Lots of them these days.
Wife's Caravan had one same symptoms. Ended up welding it solid. It has a bearing inside the pulley. Fooled me for a long time, thought it was a a/c compressor going out and didn't want to take the time to r&r it. It went a long time just chirping before the internal springs broke.




Water pump bearings could be going bad, but you need a real stethoscope to hear it early on.

Tensioner can get weak but, usually just squealing and a floppy belt is a result.

 

[BBShark]

Could it be an alignment issue? Just thinking that a slight misalignment of one of the pulleys might cause uneven tension across the width of the belt.

Does the backside (flat) of the belt wrap around the water pump pulley?

 

[mrvette]

a periodic squeak/chirp just appears.

That's usually a very early sign that a sealed bearing is starting to go.
Apparently it's gotten worse.

Check to see if your alternator has a one way clutch. Lots of them these days.
Wife's Caravan had one same symptoms. Ended up welding it solid. It has a bearing inside the pulley. Fooled me for a long time, thought it was a a/c compressor going out and didn't want to take the time to r&r it. It went a long time just chirping before the internal springs broke.




Water pump bearings could be going bad, but you need a real stethoscope to hear it early on.

Tensioner can get weak but, usually just squealing and a floppy belt is a result.

Typical, solve a problem that don't exist...dumb bastard design work....


:flash: