A mechanical combustion engine coolant pump for pumping a coolant for an internal combustion engine includes a stationary cylindrical support body. A rotatable driving wheel is supported by a driving wheel roller bearing at the stationary cylindrical support body. The rotatable driving wheel is configured to be driven by the internal combustion engine. A pump wheel is arranged at a rotatable rotor shaft. The pump wheel is supported by a shaft roller bearing at the stationary cylindrical supporting body. A switchable friction clutch is configured to couple the rotatable driving wheel with the pump wheel. The stationary cylindrical support body integrally comprises an inner ring of the driving wheel roller bearing. The stationary cylindrical support body integrally comprises an outer ring of the shaft roller bearing.