
A heat exchanger adopts a four-pass structure, including two rows of tubes, a first upper tank portion communicating with the upper end of one of the tube rows, a second upper tank portion communicating with the upper end of the other tube row, a first lower tank portion communicating with the lower end of the one tube row, a second lower tank portion communicating with the lower end of the other tube row, a communicating passage that communicates between first ends of the first and second upper...











