A multi-pass heat exchanger model OPEKS PTA (GC) -44 for the cooling system has been manufactured and is being prepared for shipment. This model has a special design, namely an increased height of the heat exchange plate and a reduced width, and also has a relief designed to increase the efficiency of heat transfer in cooling systems. The higher the heat exchanger, the longer is the path of the heat carrier in countercurrent to the other, and the smaller the temperature difference between the two heat transfer agents involved in heat exchange will be. In special cases, when the temperature difference between the media should tend, conditionally, to 0 С, we manufacture multi-pass heat exchangers. In such devices, the coolant can pass a path equal to 2, 3, 4 or more heights of the heat exchanger.