MacBook Pro - Noise - Rattle - Off & On - Almost like a vibrating sound

[Spink10]

Any idea guys?

It isn't a consistent sound....its coming from the left side near the speaker grill. Late 2013 15" rMBP

https://www.dropbox.com/s/h1nmbf63i45qhom/IMG_1520.MOV.mov?dl=0