Chevy Blazer 2001..No Heating. Replaced thermostat and plugged heater core with new now Cabin heater works fine but water pump started squealing badly within 3 minutes of run time.. Replaced water pump with new but water pump started squealing again within 5 minutes. Replaced Radiator with new to increase flow to water pump but it still squeals loudly.. Could this be a ruined water pump or something else causing this in the cooling system? Seems like low circulation flow through Radiator.

 

Do you know for certain it is the waterpump squealing? I would pull the belt and spin all the accessory pulleys by hand to make sure you are looking in the right area.

 

I bet this was a belt
If you get any coolant on the belt it will glaze over and squeal like a stuck pig