Chosen Solution
A month ago my computer started to sound very noisy, i don’t know whats happening but it sounds like something stuck in my fan. I opened it and try to see if there was something but is not. If somebody know’s what could be, tell me; because it’s sounds terrible!
Fans do fail. If it’s a screeching sound I would replace it. Here’s the part: MacBook Pro 13" Unibody and MacBook 13" Unibody Fan If nothing else remove it and shake it out. Canned air blown on it should make it spin freely if it’s not damaged.