AS6920 - Fan clicking loudly

My fan is clicking really loudly. Sometimes its fine, but sometimes its really loud. It seems to happen all the times and at random, but it seems it happens the most while I'm playing games.

I've cleaned out the dust and it seemed to have gotten better for a little bit, but shortly after the clicking came back.


Any suggestions?

edit:
just noticed something odd. if i elevate the side of the notebook closest to me, the clicking goes away...

also, i lost a screw inside my computer (one of the little ones holding the metal plate cover on the fan in place)

i cant find it... what risk does this pose to my laptop?

 

what is a reputable place to buy a replacement fan?

 

My fan has also been making noises as of late, but it's more of a burbling than a clicking or grinding.
Simply pushing down on the hub of the fan while the laptop's on seems to fix it. Already ordered a replacement from a family member who's access to a parts supplier.

In terms of risk, I wouldn't start worrying until the fan stops. I was running HD encoding on my CPU, and it barely broke 48 Celsius, speccy fan and all.

 

the fan seems to have calmed down today so im just going to leave it alone and order a replacement for backup

as for the risk, i was referring to the risk of the screw being loose somewhere inside the laptop. so far there hasnt been any problems, but im worried about the screw making contact with the board and short circuiting something...