A stacked plate heat exchanger includes a core having an outer periphery and a longitudinal axis, a shell having an inner periphery and at least partially surrounding the core to define a fluid gap therebetween. A seal between the shell and the core at least partially divides the fluid gap into an inlet chamber and an outlet chamber, and includes at least one core fin projecting generally radially outwardly and having at least one core fixed end proximate the outer periphery of the core and at least one core free end distal the outer periphery of the core, and also includes at least one shell fin projecting generally radially inwardly and having at least one shell fixed end proximate the inner periphery of the shell and at least one shell free end distal the inner periphery of the shell, and being interleaved with the at least one core fin.