Reoccurring squeak from engine

So I’ve had a persistent problem over the last two weeks or so, I get this odd squeak/squeal that occurs on start up. It’s sudle at first but gets louder as I accelerate.

I figured it was the serpentine belt so I ran over to autozone and picked one up and swapped it out. I didn’t notice any signs of wear or built up on the old belt, nor did I find any on the idler pulleys. None of the pulleys are loose and the Crank shaft, water pump, alternator, P/S pump and A/C comp. looked good as well.

I started the truck and everything seemed to be fixed, drove the truck a few days and boom the same issue. I’m confused. Judging by the sound its for sure coming from the serpentine system but doesn’t indicate to a bad bearing nor my timing chain, those are unforgettable sounds.

My trouble shooting method was spraying some water on the belt as it ran, the sound didn’t stop but it didn’t get worse. I also observed the belt while running to see if I could find any indication of belt misalignment but no luck there either.

I’ve got 246k miles. All my fluids are good and there seems to be no other issues, I do have some oil built up on parts of my engine from an oil leak years back, some near the water pump, maybe that’s causing this?

 

what brand is the belt
how old is the rest of the drive belt system
did you spray water or soapy water, and a little or a lot
Not a bad idea to do a cleaning either. Fluids can contaminate the pulleys and belt.

 

Regular water, I’d say enough to wet the belt a good bit but I didn’t pour a bucket or anything lol, I just got a cheap masterpro one to troubleshoot the issue usually run a continental which was what I had in their prior to changing (maybe 3 years old, which was odd in itself)

The drive system is at least 12 years old (since I’ve owned it) not sure if the guy before me had change anything

 

if you ask me, I’d say get an OEM brand belt, clean the area. Other brands not worth the box they’re in.

and replace the drive belt system. This is common.
Pulleys. Tensioner. Re evaluate.

It uses the same pulleys as any other car that would be worn by this point. But next someone’s gonna chime in “it has a Toyota badge you should never replace a single wear part ever” so to each his own, do what you wanna do.

At much lower miles I’ve already confirmed numerous pulleys of mine were bad, made noise, and replaced them. Meaning you probably have worn ones too. It’s a bearing that isn’t greasable. They wear. Usually safe to assume previous owner didn’t do anything.

only thing I set aside to finish later is hard stuff like the tensioner. Expected it to be a quick job while I was in there. Nope. From what I saw, it’s a PITA and blocked by the compressor and motor mount.