2004 tahoe whining not serpentine belt tensioner or idler pulley

[Vincent Mitchell]

I just replaced the tensioner, idle pulley and serpentine belt and the squeal persists. high pitched whine like power steering belts of old but no wear present on the replaced belt. What should I check next?

 

[Doubeleive]

I just replaced the tensioner, idle pulley and serpentine belt and the squeal persists. high pitched whine like power steering belts of old but no wear present on the replaced belt. What should I check next?

Did you check and or change the ac belt or tensioner?
it's pretty typical for the ac tensioner to be noisy, particularly on a cold start int he morning.
a easy way to check would be to simply pull the belt off and let it dangle, just stick a ratchet drive in the center hole of the tensioner pulley and twist to release tension.

 

[Vincent Mitchell]

Good to know. I'll try and let you know. Are new ones any quieter?

 

[Miami-Dade]

I just replaced the tensioner, idle pulley and serpentine belt and the squeal persists. high pitched whine like power steering belts of old but no wear present on the replaced belt. What should I check next?

Moved you here from the 2024 section.

 

[Doubeleive]

Good to know. I'll try and let you know. Are new ones any quieter?

it can be hit n miss

 

[strutaeng]

Yeah, just remove both belts to rule out accessories.

Also, try to make a DIY megaphone from a cut plastic jug and a long screwdriver. South Main Auto showed how to make one and seems rather effective in finding these noises that are hard to pinpoint. I'll see if I can find the video.

Edit:

 

[OR VietVet]

Get a mechanic's stethoscope and keep it handy in the tool box.

 

[Vincent Mitchell]

I replaced both tensioners and idler pully and belts. There is atill a high pitched whine that goes away if I rev it a little but comes back at idle. At this point I think I need to localize the sound. The components on upper belt are Water pump, Alternator, Power steering pump. Lower belt is AC. At least I think that's what it looks like.

@strutaeng,

I wasn't sure If i could just try removing the belt to isolate which one has the noisy bearing. Is that safe?

 

[Vincent Mitchell]

Moved you here from the 2024 section.

Thanks. I misread the section.

 

[strutaeng]

I replaced both tensioners and idler pully and belts. There is atill a high pitched whine that goes away if I rev it a little but comes back at idle. At this point I think I need to localize the sound. The components on upper belt are Water pump, Alternator, Power steering pump. Lower belt is AC. At least I think that's what it looks like.

@strutaeng,

I wasn't sure If i could just try removing the belt to isolate which one has the noisy bearing. Is that safe?

Sure. Just idle it briefly and keep an eye on temperature because your fan, water pump, etc. obviously won't be working. May be better with a helper on the cab watching while you are listening in the engine bay.

 

[Vincent Mitchell]

@strutaeng

I saw that noise finder video yesterday. I think I will try that. But I am not crazy about sticking things close to moving parts

 

[Doubeleive]

I replaced both tensioners and idler pully and belts. There is atill a high pitched whine that goes away if I rev it a little but comes back at idle. At this point I think I need to localize the sound. The components on upper belt are Water pump, Alternator, Power steering pump. Lower belt is AC. At least I think that's what it looks like.

@strutaeng,

I wasn't sure If i could just try removing the belt to isolate which one has the noisy bearing. Is that safe?

have you checked the power steering fluid level?, has it ever been flushed?
generally the power steering pump or alternator are the only things that will whine some (not necessarily squeal unless they are on a last leg).
ac pump's tend to sound like a bucket of bolts being chewed up by a wood chipper when they go out.
electric fans hum more or less

 

[OR VietVet]

If you can hear the noise instantly, when you start the engine, taking belts off and listening for the noise will not hurt anything. Remove them one at a time and start right after remove the main belt. That belt runs more components.

 

[WestCoastie]

I did the same thing you did. Replaced belts and upper and lower tensioner, plus the idler pulley.

I had the same issues, whine at start up and idle then went away while driving.

Turned out to be the bearing on the alternator pulley.

Also, if you replace belts, do your research and make sure you know what part numbers work. The good people at oreillys and auto zone have given me the wrong belts before.

 

[adriver]

I see you just replaced your alternator. The factory 105 amp alt uses a small case alt. Anything 130+ amp including aftermarket uses a large case alt. The pulley is in a different place and requires a belt that is 3/4" longer. You can install the old/smaller belt on it, but it has a lot more tension. You need to replace with the new belt. It's causing more tension on the alt pulley, and not only is it probably why you are hearing the whine, but also why you are having voltage issues.

 

[OR VietVet]

I see you just replaced your alternator. The factory 105 amp alt uses a small case alt. Anything 130+ amp including aftermarket uses a large case alt. The pulley is in a different place and requires a belt that is 3/4" longer. You can install the old/smaller belt on it, but it has a lot more tension. You need to replace with the new belt. It's causing more tension on the alt pulley, and not only is it probably why you are hearing the whine, but also why you are having voltage issues.

If this is the problem, good catch.

 

[D -money]

I just replaced the tensioner, idle pulley and serpentine belt and the squeal persists. high pitched whine like power steering belts of old but no wear present on the replaced belt. What should I check next?

Common with 5.3 alternators..dont sweat it if not compromising performance