Strange whirring noise

My Problem

The Macbook had a strange whirring noise all the time when it was on. It was getting louder day by day, so it was obvious that this problem was not going away.

My Fix

Opened computer, confirmed that the left fan was defective and ordered a new one from iFixit.

Ordered a new one. The one I got was at least free from dust, but somehow felt like it had been handled more than the original Apple fan I was replacing.

My Advice

There are directions from Apple, about how to tighten the screws in the lid on the bottom of the MacBook Pro. If done improperly, the computer might wobble on your desk. Directions are here: https://support.apple.com/en-us/HT202450 and the stuff you need is section 12.