Abstract: A coolant pump for a coolant circuit of an internal combustion engine, the coolant pump having a pump housingin which is mounted a drivable shaft, to one end of which is attached an impeller-which has vanes extending into a suction chamber and is connected to a cover plate. Fluid can be drawn into the suction chamber through an intake port of the pump housing by joint rotation of the impeller and the cover plate and can be conveyed by the vanes into the pump housing. A guide plate, which is axially displaceable by an actuation unit, is disposed between the impeller and the cover plate. The guide plate has a contour corresponding to the impeller and a collar oriented toward the impeller. The coolant pump is characterized in that the guide plate has at least one opening.