Need help diagnosing this squeal (with video)

[cwininger]

04 lx470. Started doing this today, probably has become more noticeable since the temps are dropping.

Is it idler pulley, tensioner, loose belt? Or does it sound like a water pump bearing or some other bearing?

It gets a little better as the vehicle warms up to operating temp.

 

[bigredmachine]

sounds like the top idler pulley. you can check that easily by loosening the belt, slipping the belt off the pulley and spinning it. it should be smooth with no noise, if it sounds rough or dosent turn smoothly time for a new one. or you can listen to it with something like this with the engine running https://www.amazon.com/Lisle-52500-...=1476036159&sr=8-4&keywords=sound+stethoscope, or a long screwdriver.