Right Fan was broken/worn-out and made a lot of noise, and had reduced speed (Max 2000 RPM).
Excellent, with good tools, parts and guide.
No problem for a not that tech. savvy person with this guide.
Unibody Laptop Dual Drive
Phillips #00 Screwdriver
P6 Pentalobe Screwdriver 2009 15" MacBook Pro Battery
MacBook Pro 15" Late 2008 through Mid 2012 (excluding Mid 2009 2.53 GHz) Right Fan