Join Date: Apr 2011
Location: Connecticut (USA)
Pump is "cavitating" as it's called in the pump industry - either due to air bubbles in the pump, or a bad pump. I can almost promise that you haven't gotten 4 bad pumps in a row, and now I'm not denying that something sounds wrong with that pump.. Any pump (with few exceptions) will make a noise like rocks are inside of it if it is not completely filled with liquid and void of air. I suggest flipping the radiator for starters, to ensure a steady supply of water is at both the inlet, and outlet of the pump - make sure the hoses are coming out the bottom of the radiator, not the top like in your video.. Also run the pump for five minutes without messing with it and shaking it about for a few minutes - noise should really only be heard while the system works out the initial few air bubbles until they find a place inside of the radiator to sit for a while - Operation should be nearly silent after that.