of a radiator 20 and a conduit preferably a meandering tube 22 mounted in the bottom tank the conduit 22 is assembled beforehand with the radiator bottom tank 21 thereby providing stud portions 23 and 24 at opposite ends for connection with the conduit 17 and 19 by means of proper tube connecting lock nuts 25 and 26 the fuel pump 16 in the shown embodiment comprises an inlet port 27 and an outlet port 28 these inlet and outlet ports being connected with a diaphragm chamber 31 through check valves 29 and 30 an end of the diaphragm chamber 31 is defined by a diaphragm 32 which is connected to and driven by an actuating rod 33 which in turn is driven by a cam 35 through a cam follower element 34 the cam 35 is rotated by the engine fuel supplied to the inlet port 27 of the fuel pump 16 is drawn from a fuel tank not shown through a conduit 36 and a filter 37 provided in the way of the conduit fig2 is a diagrammatical view showing another embodiment of this invention in fig2 the structure regarding the engine 1 the intake manifold 2 and the carburetor 3 are similar to those shown in fig1 and therefore repetition of a detailed description thereof will be omitted by applying corresponding reference numerals to corresponding portions in this embodiment fuel to be supplied to the fuel inlet 11 of the carburetor from a fuel pump which may be the pump 16 in fig1 is passed through a heating portion constituted as an independent heat exchanger 18 39 separated.