Two stage operation for radiator

An improvement in a water cooling system for an engine of the type that passes water through the radiator at relatively low flow rates when said engine is running in its low idle condition, said radiator comprising an upper header and a lower header interconnected by a plurality of parallel extending rows of water tubes in a core section, said improvement comprising a gate means provided in said upper and lower headers between adjacent rows of water tubes for converting the water flow through said water tubes from parallel paths to a series path upon the occurrence of said engine changing to said low idle condition.

An improvement in a water cooling system for an engine of the type that passes water through the radiator at relatively low flow rates when said engine is running in its low idle condition, said radiator comprising an upper header having an inlet opening, a lower header having an outlet opening, and three parallel extending rows of water tubes in a core section interconnecting said upper and lower headers, the first row of said water tubes being closest to said inlet opening and the third of said rows of water tubes being closest to said outlet opening, said improvement comprising a first gate means having open and closed positions disposed in said upper header between said first and second water tubes which divides said upper header into two chambers when in said closed position and a second gate means having open and closed positions disposed in said lower header between said second and third rows of water tubes which divides said lower chamber into two chambers when in said closed position, said first and second gate means being responsive to water pressure such that when said radiator water flow rate drops sufficiently the water flow through said rows of three tubes is converted from three parallel paths to a single series path.