Pump/Res making strange noise

[lewiswongy]

Hey guys I built my own water loop about 3 months ago using a XSPC X2O 750 Dual Bayres/Pump (Black) V4 and recently upon switching the pc on its started making an usual noise thats quite loud at the start and then dies down. Was wondering if I should be concerned about this? Any ideas what this might be and any solutions?

 

[OLDPHART]

Could be you have trapped air in the pump, fill the res quiet full and really tilt it from side to side to get any air out the pump.