Very loud whirring fan noise, sounds like caught on wire

[randomperson4000]

I have a mid-2011 MacBook Air and recently, its fan has been going absolutely crazy. When I use it at a table for around 45 minutes, the fan sounds like a Roomba stuck on a wire. The sound gets progressively louder, and I really don't want to see how it progresses after that. If I wait for around 30 minutes to an hour and then use my computer again, the fan doesn't make the "Roomba + wire" sound until about 45 minutes later. This issue has been going on for two days.

 

[cruisin]

Something in the fan is stuck or the bearings are worn out.

You need to go to the Apple store and they will either blow it out or sell you a new fan (about $20 plus labour). Or you can blow it out yourself or buy the fan yourself.