My macbook is screaming at me...
 

Damn it. Figures. Fan going to hell in my macbook pro... Not surprised since it's basically been on for the last 5 years. Looks like the parts 40 bucks and takes about 40 minutes to fix.

If the fans are making a loud noise like they are broken all you need to do is take apart the fans and put sewing machine oil on the axel with a q tip and it will be quiet again. Worked on my macbook pro.

Better to replace the fan properly so you're not having to re-oil the bearings every few months. Sewing machine oil won't last long.

Yeah for $40, id be fixing it the right way.

But then again, 5 years.. You may start seeing other issues soon too.

Fix it properly, oiling won't last long while the weather is hot. Not a good time of year to let it overheat.

Have you tried to clean it?
Maybe it's because of dust...