Help with idle noise- pulley / belt?

I’ve been trying to diagnose a noise I’m having during idle. 2013 V6 4x4.

Happens sitting still and slow speeds, and at highway speeds gets drowned out by wind noise. Very intermittent and random noise. Not affected by steering or using heat / ac. I’m thinking it could be a pulley going bad or bad belt? Doesn’t squeak or chirp, but it honestly sounds similar to an old computer loading or an old school printer.



I have sprayed wd40 on the belt to see if the noise changes but no dice. Also burped the air from the radiator after a coolant drain and fill, no air present. Tried higher octane fuel, no change. Any ideas what this could be?

Thanks in advance for any help.

 

Probably time to just replace them both. I’m getting ready to do mine 2012 4.0 140k

 

Sounds like a bad bearing in a pulley, take your belt off and wiggle/spin all your pulleys if you find one that's noisy or loose that's likely what your hearing. Another option is if you have a long screwdriver or something similar that you can use for a stethoscope you can put it on or near each of the pulleys and put your ear to it and isolate it that way, just take care not to hit the fan or get it in the belt.

 

Replaced the serpentine belt and checked the pulleys but they were fine. Still hearing the noise. Honestly you can hear it louder in the cab than under the hood. Any other ideas what this could be? Thanks guys.

 

Is it your blower motor? Mine was bad 3 months from new and then again at 50k.