A pump group (1) for a cooling circuit of an engine comprising a pump body (2), a rotor (3) and adjustment means (10) suitable for adjusting the amount of liquid moved by the rotor (3) Wherein the adjustment means (10) comprise: i) a valve group (100), which extends along a main axis (X-X); wherein said valve group (100) comprises an obturator (130) rotatable around the main rotation axis (X-X), suitable to be moved into innumerable angular positions in which it permits, partializes or obstructs the passage of coolant liquid; ii) an actuating device (200) engaged with the obturator (130) comprising an electric motor (210) suitable to adjust the angular positioning of the obturator (130) in the aforesaid angular positions.