rygiric88

I have a 2018 Navigator L Reserve, 3.5l EB, roughly 65k miles. For the last 2 months or so i have been trying to figure out what is making a chirping/squealing noise under the hood. I have replaced the serpentine belt 2x and that worked for a couple weeks then the noise was back. I most recently replaced the idler pulley and that was not the issue. i am working on replacing the tensioner but I dont "think" that will fix it either. i hope it does but i dont think that is the issue as that pulley "appeared" ok. i am just struggling to narrow down the location of the noise. any other ideas out there? a few other points before anyone responds: I still need to check out the harmonic balancer but i would assume with 65k that it is still in good shape? the alternator pulley and water pump pulley "appear" to spin free and are in good condition. when i remove the belt and start the vehicle for +-10 sec the noise is absolutely gone, so i believe that eliminates cam phaser/exhaust leak issues. noise has progressively gotten worse over the last couple weeks, and it doesnt matter if it is a cold or warm startup. There isnt much info on my issue online regarding a Navigator but i know it has the same engine as the f150 and Raptor so i am hoping someone on that side may have run into this issue and has a solution. i really dont want to take it to the dealer for work. i am fairly mechanically inclined but i dont want to rip stuff apart just for trial and error without knowing what the issue is. Thanks for any help/ideas.