Cast plate heat exchanger with tapered walls

A heat exchanger comprising:

• a plate including a plate portion, an inlet end portion and an outlet end portion, the plate portion having outer walls and a plurality of internal passages extending between the inlet end portion and the outlet end portion, wherein a ratio between an outer wall cross-sectional thickness at one of the inlet end portion or the outlet end portion and a cross-sectional wall thickness of the outer wall within the plate portion is greater than 2.5 and no more than 10, wherein the plate portion includes a plate width between a leading edge and a trailing edge, an end width between outer surfaces of the peripheral walls in the same direction as the plate width with the end width greater than the plate width and a tapered transition between the plate width and the end width at one of the inlet end portion or the outlet end portion, wherein the tapered transition includes an increasing wall thickness in a direction from the plate portion toward the at least one of the inlet end portion or the outlet end portion;
• an inlet manifold attached to the inlet end portion;
• and
• an outlet manifold attached to the outlet end portion, wherein each of the inlet end portion and the outlet end portion include a face surrounded by peripheral walls and the peripheral walls define the outer wall cross-sectional thickness.