A liquid-cooled internal combustion engine having at least one cylinder with a cylinder head in which there are disposed a lower partial cooling chamber adjacent to a fire deck and an upper partial cooling chamber which is flow-connected thereto by way of at least one main overflow aperture. The substrate has at least one power transforming circuit and at least one pair of power input holes. The water quality apparatus is typically a pipe fixture having an outlet end that fits into the control structure and an inlet end comprising several perforated pipes that protrude into the semi-round pipe.