[ricg]

About your MacBook fans squealing: I had the same problem with my 2012 MacBook Pro. It turned out that the grilles through which the fans blow out the hot air were completely clogged up with dust and the Macbook would overheat.

I cleaned both and now the fans rarely spin up to full speed, because the hot air can actually leave the case again.

See this guide (the guide does not show cleaning the grille, but that is the important part).

https://www.ifixit.com/Guide/How+to+clean+your+MacBooks+fan+...