Abstract: A plate and fin type heat exchanger is disclosed for cooling automotive engine oil, transmission fluid and power steering fluid. The heat exchanger is formed of a plurality of stacked plate pairs with louvered fins located therebetween. The plate pairs are formed of two elongate identical plates located face-to-face and having planar central portions, raised co-planar peripheral edge portions joined together, and co-planar end bosses with openings therein to form flow headers when the plate pairs are stacked together. The planar central portions have a plurality of uniformly spaced-apart, on-overlapping blunt projections joined together along a common plane with the peripheral edge portions. The projections are symmetrical and provide uniform flow through the plate pairs.