An adjustable coolant pump comprising: a housing; a shaft to rotate around an axis of rotation of the housing; an impeller assembled in the shaft; a shutter displaceable along the axis of rotation to cover, at least partially, an outflow region of the impeller such that an amount of the coolant delivered by the pump is adjustable; wherein the housing comprises: a top face and a bottom face disposed substantially perpendicular to the axis of rotation, the bottom face being provided between the top face and the shutter; an annular wall extending from the bottom face in axial direction in such a way that a cavity to receive the shutter is defined at least by the annular wall and the bottom face; wherein the adjustable coolant pump further comprises: an adjustment sealing arrangement provided between the shutter and the annular wall, the sealing arrangement comprising a ring seal attached either to the shutter or the annular wall in such a way that a dynamic sealing between the shutter and the housing is defined and a shaft seal disposed around the shaft, characterized in that the shaft seal is in fluid communication with the cavity; wherein the outflow region is in fluid communication with the cavity through a shutter hole provided in the shutter and wherein the sealing arrangement allows a flow of coolant therethrough and from the cavity when the pressure in the cavity is above a predetermined threshold. a housing; a shaft to rotate around an axis of rotation of the housing; an impeller assembled in the shaft; a shutter displaceable along the axis of rotation to cover, at least partially, an outflow region of the impeller such that an amount of the coolant delivered by the pump is adjustable; wherein the housing comprises: a top face and a bottom face disposed substantially perpendicular to the axis of rotation, the bottom face being provided between the top face and the shutter; an annular wall extending from the bottom face in axial direction in such a way that a cavity to receive the shutter is defined at least by the annular wall and the bottom face; wherein the adjustable coolant pump further comprises: an adjustment sealing arrangement provided between the shutter and the annular wall, the sealing arrangement comprising a ring seal attached either to the shutter or the annular wall in such a way that a dynamic sealing between the shutter and the housing is defined and a shaft seal disposed around the shaft, characterized in that the shaft seal is in fluid communication with the cavity; wherein the outflow region is in fluid communication with the cavity through a shutter hole provided in the shutter and wherein the sealing arrangement allows a flow of coolant therethrough and from the cavity when the pressure in the cavity is above a predetermined threshold. a top face and a bottom face disposed substantially perpendicular to the axis of rotation, the bottom face being provided between the top face and the shutter; an annular wall extending from the bottom face in axial direction in such a way that a cavity to receive the shutter is defined at least by the annular wall and the bottom face; wherein the adjustable coolant pump further comprises: an adjustment sealing arrangement provided between the shutter and the annular wall, the sealing arrangement comprising a ring seal attached either to the shutter or the annular wall in such a way that a dynamic sealing between the shutter and the housing is defined and a shaft seal disposed around the shaft, characterized in that the shaft seal is in fluid communication with the cavity; wherein the outflow region is in fluid communication with the cavity through a shutter hole provided in the shutter and wherein the sealing arrangement allows a flow of coolant therethrough and from the cavity when the pressure in the cavity is above a predetermined threshold. an adjustment sealing arrangement provided between the shutter and the annular wall, the sealing arrangement comprising a ring seal attached either to the shutter or the annular wall in such a way that a dynamic sealing between the shutter and the housing is defined and a shaft seal disposed around the shaft, characterized in that the shaft seal is in fluid communication with the cavity; wherein the outflow region is in fluid communication with the cavity through a shutter hole provided in the shutter and wherein the sealing arrangement allows a flow of coolant therethrough and from the cavity when the pressure in the cavity is above a predetermined threshold.