A stacked-plate heat exchanger may include a high-temperature (HT) coolant circuit, a low-temperature (NT) coolant circuit, heat exchanger plates stacked upon one another and through which two coolants and a medium to be cooled may flow, and an obstruction configured to force a deflection of one of the coolants in the low-temperature coolant circuit. The two coolants may have different temperature levels in the high-temperature and low-temperature coolant circuits. The heat exchanger plates may include a partition wall separating the high-temperature and low-temperature coolant circuits from each other. The high-temperature and low-temperature coolant circuits may include a central HT coolant inlet and a central NT coolant outlet, respectively, adjacent to the partition wall and together forming a teardrop shape separated by the partition wall. The HT coolant inlet may have a part-circle-like shape and the NT coolant outlet may have a triangular shape, each having one side formed by the partition wall.