PURPOSE: To form the radiator having a strong structure for an internal pressure, an excellent heat exchanging function and a structure to be easily manufactured as a cooling system radiator for an engine heating by a method wherein plural pipes having nearly circular section are communicated between an upper tank and a lower tank, and the pipes are wrapped integrally with a metallic foam.

CONSTITUTION: Both of an upper tank 7 and a lower tank 8 are provided with holes to which the end parts of pipes 10 having nearly circular section are inserted for forming connecting parts. Thereby, the both tanks are communicated smoothly through each other with pipes 10, and connecting parts are made to be airtight. The whole body of those pipes 10 are made to be integral forming by wrapping with a metallic foam 11 having excellent thermal conductivity such as aluminum of copper, thus a radiating part 9 is formed. The foam part is composed of reticulate continuous cell, and desirable to be free for air moving in and out. The metallic foam 11 is obtained by following process, that is, a plastic foam such as a urethane foam and the like is coated with a carbon, then deposited with a metal such as a nickel and the like, further, heated up to high temperature for burning the plastic out, finally, a spongy metallic foam is left. This process is most desirable method, because the rate of foaming is increased up to 90%.