A variable flow electric water pump for use in an engine coolant system of a motor vehicle, the electric water pump comprising: a pump housing defining a fluid chamber and a motor chamber, said fluid chamber including a fluid inlet and a discharge outlet for providing flow of a coolant through said fluid chamber; an electric motor disposed within said motor chamber of said pump housing and including a stationary stator assembly and a rotor unit having a rotor shaft supported for rotation about a longitudinal axis and extending into said fluid chamber; a pump member fixed to said rotor shaft for rotation in said fluid chamber and operable to pump coolant from said fluid inlet to said discharge outlet; and a biasing arrangement for normally locating said rotor unit in a first position that is axially offset relative to said stator assembly for locating said pump member in a retracted position within said fluid chamber to provide a low flow characteristic between said fluid inlet and said discharge outlet when said pump member is rotatably driven by said rotor shaft at a low rotor speed; wherein rotation of said pump member at a high impeller speed causes said rotor unit to move into a second position axially aligned with said stator assembly and causes said pump member to move into an extended position within said fluid chamber to provide a high flow characteristic between said fluid inlet and said discharge outlet, wherein said biasing arrangement is a mechanical biasing arrangement including a biasing member configured to exert a preload on said rotor unit and said pump housing includes an interface between said fluid inlet and said fluid chamber defining a first and a second flange surface (78,80), wherein said impeller having an upper first and second rim surface (136, 138) aligned with said first and second flange surface (78,80) of said pump housing, wherein a large clearance gap is established between said upper first rim surface of said impeller and said first flange surface of said pump housing when said impeller is located in its retracted position, and wherein said large clearance gap is configured to decrease the coolant flow rate between said fluid inlet and said discharge outlet. a pump housing defining a fluid chamber and a motor chamber, said fluid chamber including a fluid inlet and a discharge outlet for providing flow of a coolant through said fluid chamber; an electric motor disposed within said motor chamber of said pump housing and including a stationary stator assembly and a rotor unit having a rotor shaft supported for rotation about a longitudinal axis and extending into said fluid chamber; a pump member fixed to said rotor shaft for rotation in said fluid chamber and operable to pump coolant from said fluid inlet to said discharge outlet; and a biasing arrangement for normally locating said rotor unit in a first position that is axially offset relative to said stator assembly for locating said pump member in a retracted position within said fluid chamber to provide a low flow characteristic between said fluid inlet and said discharge outlet when said pump member is rotatably driven by said rotor shaft at a low rotor speed; wherein rotation of said pump member at a high impeller speed causes said rotor unit to move into a second position axially aligned with said stator assembly and causes said pump member to move into an extended position within said fluid chamber to provide a high flow characteristic between said fluid inlet and said discharge outlet,