40 minutos - 1 hora
Old fan was ratling first and afterwards bearings were so broken that fan became solid object.
Repair was a no-brainer taking few screws out and replacing old for a new one. I could say that ppl who haven't ever disassembled macbook it would take hour or two, but if you're accustomed to open macs, it could take 15-20 minutes. I was more concerned how the new fan would sound like.
I should have changed the fan little bit earlier, i would have been saved that horrible broken fan noise. And remember to clean all dust from copper radiator when you replace fan.