Seagate HDD noises

I know, I know, probably shouldn't have gotten a Seagate. But it was on sale and cheap.

My 1TB Seagate Barracuda started making grindy noises yesterday. Not super loud or anything huge sounding but at random times for a few minutes at a time it'll sound like a tiny machine gun battle in my HDD. Then it'll just stop for a bit. I was playing some games and it wasn't doing it but sitting at the desktop it was. Anyone know the cause of this?

I have no money for a few more days to pay for shipping to RMA which is probably what I'll end up doing.

And I know grinding isn't bad and could be the sign of it being damaged/defective but does anyone know the SPECIFIC cause?