Case fan is making a buzzing noise until I hit with a small force

[sprouze]

My 3 Months old custom-built gaming computer's case fan is now making a little buzzing noise when I start the PC up, I dunno if it keeps on going because when it's started up and on the desktop I hit with a very small force to make it stop (It's a fan in the back of the case, so I just hit it on the case infront of the fan ofc.)
I wanted to hear what could cause this before I start pulling it apart, I can barely remember how all the cables should fit. The fan seems to be spinning at the same RPM as the other case fan which is in the top.
The case is a NZXT s340

Here is the link to the full build if it matters:
http://pcpartpicker.com/user/sprouze/saved/yscnTW

 

[envy14tpe]

Just replace it. Easily done and you probably could find a better one even on the cheap side.

 

[sprouze]

Just replace it. Easily done and you probably could find a better one even on the cheap side.

Hmm okay. I'm gonna keep it for now, as it doesn't really pose a threat to the pc.
I just moved home, so I'm trying to save my money as much as I can and I'd like to upgrade to 16gb of ram soon aswell.

Thanks for the answer