That is belt squeal, Easy test, take a spray bottle or just some water and with it running spray some on the belt in the wheel well between the AC and the crank pulley. The bearing in the pulley on them can cause a lot of drag when they start to fail. The other main screamer could be the alternator. Use the water and see where using it changes the sound. You say it goes away after a while so that sort of makes me think it's alternator, If you let it stop, then turn on the lights and heater blower to high does it start again? Another trick to spot a binding item, take a piece of chalk or a marker and with the engine off draw a line across each of the pulleys. Then have someone start it while you watch them.
The last thing is that it could simply be the belt is loose. Both of those have manual tensioning instead of automatic, so as a belt wears and stretches it will need to be tightened. To do that the images below show the locations of the tensioner bolts. You loosen the pivots on the alternator and tighten the bolt to put more tension on the belt. To measure if it's correct, simply push down on the center area between the two pulleys, it should move about one quarter inch. Tighten the pivots back down, then start it and see if the noise is gone. To adjust the other belt you go to the pulley between the PS pump and the AC, loosen the center bolt on the tensioner and use the indicated bolt to tighten that belt to about the same amount. Try it again, if it's quiet you're done.
Images (Click to enlarge)
Saturday, April 17th, 2021 AT 2:34 PM