Abstract: In a liquid-cooled cylinder block and crankcase in an open-deck construction, a displacement body is placed in the coolant space. The shape of the displacement body approaches the shape of the coolant space. The interior wall of the displacement body, together with the exterior surface of the cylinder block containing the cylinders, bound a narrow gap which is connected with the coolant inlet connection. As the result, the coolant is forced to flow along the cylinder block so that an intensive cooling is achieved with a reduced coolant quantity.