Water pump impeller blades

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quick cooling system primer:

water is ALWAYS circulating through the engine, regardless of whether the thermostat is open. to properly flush the block, remove the water pump and force fluid into the CENTER hole behind the water pump. this reverse flow fluid through the block first, then the heads, & then back out through the OUTER two holes behind the water pump.

when the thermostat does open, flow is FROM the block TO the radiators THROUGH the thermostat (true on all cars). water returns from the radiators to the engine & enters the engine on the left hand side of the car through the oil pump housing.