A motor vehicle tube and fin heat exchanger is disclosed comprising a plurality of tubes arranged in spaced side-by-side relationship and a plurality of louvered fins arranged in spaced side-by-side relationship and between and in heat transfer relationship with adjacent ones of the tubes. The fins preferably have a thickness and stacked density such as to constitute not more than 12% nor less than 2.5% of the space between the adjacent tubes, a total louvered area not more than 60% nor less the 40% of the total fin area, and a linear fin edge projection density of not more than 1.2 mm-1 nor less than 0.68 mm-1.