A coolant pump for an internal combustion engine. The coolant pump includes a delivery duct, a drive shaft, a coolant pump impeller arranged on the drive shaft to rotate therewith and to convey a coolant, and an adjustable control slide which controls a throughflow cross-section of an annular gap arranged between an outlet of the coolant pump impeller and the surrounding delivery duct. The control slide comprises a first pressure chamber arranged on a side of the control slide facing away from the coolant pump impeller and a second pressure chamber arranged opposite thereto. A control pump includes a control pump impeller arranged at the drive shaft to rotate therewith. A connecting duct fluidically connects the flow duct to the second pressure chamber. A pressure duct fluidically connects the flow duct outlet to the first pressure chamber. A valve opens and closes a throughflow cross-section of the pressure duct.