So if i understand it correctly your fan/fans are going to the dump. From my limited personal experience, ive encountered a problem where my fan would start making weird noises, at first it was like scratching, then got louder after a few months to a point where it would work like a tractor. Loud noises, like something was touching that was not suppose to. After i oponed the laptop, removed the heatsink, i noticed that the casing of the fan was scratched. This led me to believe the blades are somehow moving around, i googled found out that after a bit of time the fans wear up and become “wobbly”, they move around and probably touch the casing of the heatsink on top, or the casing of the fan itself. If that is the case for you, replacing the fans would be the best option. I dont recommend the path i took of bending the metal that connects to the heatsink and is around the fan so the blades even if wobbly wouldnt touch it. But i think that might mess up the heat exchange.