Pulley Bearing Noise???!!!

[NotJLB]

Thanks all.

Yes, the squealing gets louder when we accelerate, then quiets back down when idling/coasting. When we first heard it a couple weeks ago, we mistook it for pinging because of that, so thought we got a bad tank of gas. Not the case.

I found a few videos diagnosing this problem, the same squealing noise, and they were looking at the belts, the idler pulleys, and, something I had not thought of, alignment of pulleys.

Two of the videos placed a straight edge between pulleys, found they were not aligned, adjusted one, and the squealing went away.

Added: I am not certain, but our alternator pulley could be just a tad off from the next one down that I used for a straight edge. I'm waiting for my guy to get back to me.

 

[Donald]

As recommended above, replace the tensioners and the belts. It is a reasonably cheap job, using parts from Rock Auto, and it is an easy job to perform.

I recently replaced my A/C tensioner, (as the spring failed) and at the same time, I replaced both the A/C belt and the serpentine belt. The job took less than 2 hours.

Yes, just had a bearing fail in my 07 Denali at 140k miles at 15 degrees OAT. Shredded the belt but who needs the A/C at those temps. When back home teplaced all belts, tensioners/idlers. Not expensive and done in a little over an hour. Good preventive maintensnce!

 

[NotJLB]

I thought I updated this, but I guess not.

When my guy looked at it, he saw that the pulley that I was using to get a straight edge to the alternator pulley was not pulled on flush, so he did that first. The squeal went away.

He replaced the serpentine belt any way, and he showed me a shiny spot on the crank pulley from where the belt had been a tad off.

Now that I had this issue, I'm hearing a lot of vehicles that have the same sort of squeal. Maybe they just need a pulley aligned.

 

[OR VietVet]

I thought I updated this, but I guess not.

When my guy looked at it, he saw that the pulley that I was using to get a straight edge to the alternator pulley was not pulled on flush, so he did that first. The squeal went away.

He replaced the serpentine belt any way, and he showed me a shiny spot on the crank pulley from where the belt had been a tad off.

Now that I had this issue, I'm hearing a lot of vehicles that have the same sort of squeal. Maybe they just need a pulley aligned.

Or the belts are so old and dry they squeal thru the pulleys for that. Especially if they are cracked. Or there is a fluid leak getting on them from somewhere. Or they are just cheap brand belts. The list goes on. But yes, misalignment and wrong belt size can cause problems.

 

[NotJLB]

Jan. 24:

I found a few videos diagnosing this problem, the same squealing noise, and they were looking at the belts, the idler pulleys, and, something I had not thought of, alignment of pulleys.

Two of the videos placed a straight edge between pulleys, found they were not aligned, adjusted one, and the squealing went away.

Added: I am not certain, but our alternator pulley could be just a tad off from the next one down that I used for a straight edge. I'm waiting for my guy to get back to me.

Kinda funny, when I posted this, the video showed the guy adjusting the alternator pulley, which he did by having to pound the bushings forward.

I mentioned that to my guy and he just chuckled, because of what people on the internet post. Then he said that the lower pulley was not pulled flush on mine (which might have been the case with the video one, too), and that if you move the bushings, they will just get moved back to where they were.

 

[OR VietVet]

I have swapped alternator pulleys on alternators before. When the pulley is removed there was a bushing that kept the pulley set away from the front face of the alternator case that kept it from rubbing the case when spinning. The only way to adjust it is the changing of the bushing for more or less thickness. If the alternator had an internal fan or external fan that came in to the equation as well. I have never "pounded the bushing" to adjust an alternator pulley. The mount of the alternator can also cause a difference and sometimes a shim was used.

What "lower pulley" are you talking about? Harmonic balancer pulley?