06 V8 squealing noise from alternator pulley

Can I just replace the alternator pulley without messing around with the alternator itself? I'm not having any issues with the alternator, just that the pulley squeaks non stop when idling.

 

Never heard of an alternator pully making noise. The bearings are internal to the alternator. If one is going bad, it will travel up the shaft to the pully and make it sound like pully is making the noise. I had this issue on my Tundra (same motor). Electrically, the alternator was fine, it was just the bearing. I limped it for about a year by spraying some lube in it. It would quiet for about 2-3 months.

To rule out the belt, you can dab a little grease or belt dressing on the belt. Do both sides and each edge while the engine is off, in a couple different spots.
Belt squeaks usually indicate a dry belt and an early warning for it to be changed. That is, if its not loose which means the tensioner is worn out.

 

If you're sure it's the alternator, you need to replace it, not just the pulley, as mentioned it would be the internal bearing/s making the noise.

You may want to check the idler and tensioner pulleys to see if it's not those making the noise instead of the alternator, but it would be the same in that it would be the bearings on these pulleys making the noise, except in the case of a seized pulley bearing in which case it would be the belt making the noise as it slips on the frozen pulley.

As far as putting something on the serpentine belt, you can put any product made for putting on the belt on it....BUT whatever you do DON'T put any "grease" or oil, etc. on the belt, grease or oil, etc. will degrade the belt and possibly cause it to break!!

 

Im not saying coat the entire belt with grease....
Im saying a dab. Yes a constant coating will deteriorate rubber. But not a dab. If you have ever felt a coolant hose that has been coated in oil over time, you know.

A dab will not hurt it. In fact, it is a very useful diagnostic tool to help locate and possibly eliminate squeaks.

 

I disagree, but you have a right to your own opinion.

A coolant hose and a serpentine belt are made of different rubber compounds, even coolant will degrade a serpentine belt.

 

I'm pretty sure the squealing is coming from the alternator but I'm doing an oil change this weekend so I think I'll just replace the serpentine belt and check the idle pulleys to see that they spin free. I have just under 64,000 miles and the timing belt and serpentine belt were replaced together back in 2021 but from my experience you can get a bad serpentine belt and changing it is easy and relatively cheap. If the noise continues from the alternator I can always replace that too. While its not the easiest alternator to replace, from what I've seen its not really that big of a pain. I'll try what DIRTRCR13 did and spray some lube around the alternator pulley and see if that quiets it down. If it does I'll just go with it until it starts squeaky again and then replace.

 

So today I changed the oil/filter, rotated the tires and put on a new Gates serpentine belt. It had much tighter, narrower groves than the belt it replaced. I drove around for awhile and let it sit idling and so far zero squealing. Hopefully that was the culprit and the alternator/pulley is good.