Help with strange noise coming from case fans

[jwag598]

So I bought the Cooler Master X RC-942, got my computer built and working. But the two exhaust fans on top (I bought a COOLER MASTER Megaflow 200 R4-LUS-07AR-GP 200mm Red LED Case Fan) when ever they're running, a sound like its hitting a wire comes from both of them. I checked and I'll check again, but I'm pretty sure that there is no wires from the front I/O panal hitting it or any other wire hitting it.

Thanks in Advance

 

[seller417]

slightly warped fan?

 

[jwag598]

Sorry I was thinking it was something like that or had to do with the manufacturer, but in fact it was a stray zip tie tail. But thank anyway

 

[jwag598]

Best answer selected by jwag598.