Abstract: A cooler unit housing is located in a passenger room near a dashboard of a motor vehicle. A piping arrangement of the cooler unit comprises a pipe joint which is positioned at and supported by an opening of the dashboard. The pipe joint has a first face facing toward the passenger room and a second face facing toward the engine room. An expansion valve unit is connected to the first face of the pipe joint. Coolant inlet and output pipes are arranged, each having one end connected to an evaporator in the cooler unit housing and the other end led to the expansion valve unit. A grommet is disposed between a peripheral portion of the opening and an outer wall portion of the pipe joint thereby to establish sealing therebetween.