Non-Stuck valve AIP question

I'll first get this out of the way. No Codes, no drivability issues yet. I know theres a lot of AIP posts but I can not find one with this pacific mention or question, and most of them I see are stuck Valves O/C.

I'm still not 100% it is the AIP, but heres the story.

so a few months ago after a cold start (won't do it if it's restarted later in the day) I started getting a faint belt squeal on start that seemed to go away with in 4 minutes or less after start up. I listened and placed the noise on the passenger side of the engine bay. I figured it was probably my belt tensioner binding and after so long it would break free so I ignored it. Fast forward to a few days ago on start up I decided to hit the gas and see if it would squeal like a belt with more RPM the noise didn't respond and seemed to have stopped after hitting 1,500rpm and letting off. This got me thinking of the two AIP tank looking things that sit in the same area of were I thought I had a faint belt squeal. Today I decided to first pop the hood, turn off all accessories and after cold start I went over and to the spot and tried to locate it, with the hood open its harder to hear over the 5.7s wind it puts off. It maybe lasted 1 minute and half but instantly stopped when what sounds like a air pressure purge happened from the intake.

1.) So my question are what is the cause of this purge after start up? (I'm sure the purge is normal but will help identify the related systems that could be squealing)
2.) is it common or a symptom for a AIP tank to squeal on start up.

any help is appreciated, especially since diagnosing this is hard due to it only happing for 1 minute and 30s every 24 hours.

 

I think your squeal is a bearing in the drive belt system (tensioner, idler, steering pump, alternator). I suppose it could be the Air Pumps. Good luck.