[jing]

https://www.youtube.com/watch?v=RTH71DREIvg

2006 Toyota Camry 4cyl

Car hasn't had any recent service besides an oil change a couple months back. Belt looks fine.

What's the issue? I'm guessing it's one of the pulleys. Is there a recommended way to diagnose this?

[SpeedStars]

Did you recently have the accessory belt changed or noticed anything up with your battery? My prelude used to do this when the serpentine belt was too tight and when the alternator was failing. Try turning on the AC or radio and see if the noise gets louder.

[jing]

Belt hasn't been changed since new lulz. Nothing different with the battery either. I'll try the AC/radio trick. Looks like I'll need a stethoscope to figure out where the sound is coming from.

[fliptuner]

My guess would be an accessory bearing or belt. Alt, PS, muffler, AC

[jing]

Muffler bearing? I recently changed that already with a Mashimoto ZX model.

[SilverBlitz]

https://www.youtube.com/watch?v=hmPUUVwIJUU

[ssjGoku69]

try removing the Serpentine/Accessory belt and see if the noise is still present

[320icar]

I've had this multiple times on various vehicles, has been either failing alternator bearing or AC pump (on or off, had to cut AC belt on road trip with pocket knife)

[jing]

I'm noticing a slight burning smell as well. Signs are pointing towards failing alternator.

[Raid3n]

try doing what they did in the video, unplug the alt while it's running and see if the sound stops.

[bcrdukes]

Likely alternator.

Open/close all four windows (assuming they are powered?) and it will have enough of a draw on the system.

[fliptuner]

try removing the Serpentine/Accessory belt and see if the noise is still present

I'm pretty sure if nothing is turning and there's no belt, the noise won't be there either. Lol

[k3mps]

pretty certain it's the alternator. try unplugging the alternator harness then starting the car. If it doesn't make the noise, then you know what the problem is.

any brake light / abs light?

[YammieNoob]

It's the alternator most likely. Same noise happened to me on the highway. When I opened up my hood the alternator smelled like it was burned. Cheap and easy fix to change the alternator yourself.

[jing]

'twas the alternator

Side note: The serpentine belt was strangely difficult to put back on. I had to route it in place then wedge the alternator back in as I cranked on the tensioner.