Im new to the forum and I'm sure if there is a thread for this, but here goes.

I just got a 2003 silverado ext cab 5.3l z-71 pickup. When I start my truck its sounds fine, however it starts to whine low on idle and gets louder with acceleration. I have replaced the altenator thinking it could be that. No. still squeals like before so no need to change it but way she goes. Replace the serpentine belt thinking its quite old maybe thats whats squeaking. No. Infact now when I accelerate (softly) it sounds like the spawn of satan is screeching under my hood, and not in a good way. Im thinking now it could be a pulley or something. Im by no stretch of the imaginaton a mechanic so its probably something simple that i overlooked.

If there is anyone that might know whats going on and how it could be fixed, Im open to suggestions.

Thanks.

 

Well it has to be rotational. Have you checked the tensioner pulley or idler out? Possible water pump or fan possible.

 

Well being that I have a new belt, I know it has to a pulley. I'm really leaning toward tensioner pulley. But it could be anything though. I'm pretty sure none of these pulleys have been changed. It was my grandfathers truck he bought brand new and has been used as a work truck for quite a few years. It also has 160,000km and change. I saw on the internet to use a screwdriver and cut off milk jug to to listen to each pulley.

 

I've replaced idlers and tensioners many times. You may be able to remove the belt and check each pully for play and spin them by hand to see how easy they do turn.

 

Alright I'll check them out and see if there is anything out of the ordinary.

 

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• So before i checked the pulleys I did a water bottle test. So when my truck fired up it was fine. When I sprayed all the pulleys it didnt squeal, except one. I believe (if I know the pulley) is the power steering pulley? I rotated them all and no real grinding. The pulley to the passenger side of the altenator, if you quite literally put your ear to it you could hear a faint grinding noise. As for the power steering pulley I can wiggle it maybe 1mm-1.5mm. Everything else seems solid. But maybe that movement is enough to make the belt squeal? Researching around other forums with similar problems and a harmonic balancer was a posssible culprit? Also I have a tensioner pulley system on the way. Anyways thanks for the help.
  

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Sounds like you've narrowed it down to a couple possibilities. Let us know what it was when you have it fixed.

 

So I replaced the tensioner pulley assembly and it still squeals. The sound seems to be coming from the the power steering pulley. When I poured water on it, it didnt squeal this time though. It seems very random when it does it. When I first fired it up, squealed very loud. Turned off, turned back on and not a single sound. Revved it and no squeal. Turned it back on, let run for a bit then it started to squeal again. Turned off, back on and it stopped. So as you can see it is pretty random. Will pulleys cause this sound. Could a power steering pump or related part cause this sound?

 

Could be power steering pull. Kind of stumped myself on that one. But you did mention it has some play in it.