I get a lot of folks with water pump problems so here is a tidbit to see what condition your pump is in. While the pump is off and after replacing the impeller, block one of the ports and suck through the other. If you suck air, either front seal or Oring is leaking. Then unblock the port and blow through the pump. Easy to blow? Pump is worn and will not suck water. Hard to blow through, pump is tight and probably not a problem.