My fan ran way much more often and faster than when my computer was brand new.. and started to annoy the sh*t out of me.
After cleaning the inside of the computer with loads of wet (only on non electronic parts) & dry wipes and compressed air i still couln't get off all dust inside the fan. So i thought i'd get a fresh one to replace it with and then try to clean the original fan and put then in "circulation" ;)
It wen't just fine. It was a little bit tight and tricky but the video guide helped out. Only thing i wish was more clear would be a notice in the video that the screws holding the fan are different sizes, which i didn't notice until it was time to screw it back together and gave me som headache.
Also, a notice: the fan sold as "new" on ifixit had minor dust stains on the blades it and also had a dent on the big "vent hole". So it sure wasn't new or even in mint condition. Little bit dissappointing.
The replacement sure did some improvements on the fan sounds but it's still much worse than when then computer was new. So now i'm killing processes and uninstalling software. Considering a system reinstall.
Use a very careful system to keep track on where each screw belongs :)