I've had this WC setup for 3 months already working fine. I changed the coolant 2 times. I think I suspect the pump, because yesterday when I turned it on it started to make annoying swishing sounds repeatly. I changed out the coolant, tried to bleed it agian but the sound wont go away the entire time. I did all things like supspending the pump higher , but no luck. This is my pump http://www.svc.com/ddplm.html What does this probally mean from the symptoms?