Abstract: A plate-type heat exchanger (30) for a vehicle cools a cooling fluid by means of a coolant. The exchanger (30) has a plurality of heat exchanger plates (40) which are stacked one on top of the other. Coolant chambers (44) and cooling fluid chambers (46), which each have an inflow (48, 52) and an outflow (50, 54) for the coolant and/or the cooling fluid are formed between adjacent heat exchanger plates (40). The coolant and/or cooling fluid chambers (44, 46) are embodied in their entirety as U-shaped flow ducts (64, 68), wherein the assigned inflow (48, 52) is arranged at the end of a first limb, and the assigned outflow(50, 54) is arranged at the end of a second limb, of the flow ducts (64, 68). The invention also relates to an air-conditioning circuit (10) for a vehicle.