Abstract: A hermetically sealed low pressure, low temperature cooling system for internal combustion engines which include a thermostat that operates at a predetermined temperature, typically 195.degree. F. Thermostatic control of engine operation temperature is maintained at or in relatively close proximity to this predetermined temperature thereby eliminating overheating and corrosive deterioration of the cooling system. Free coolant flow between the radiator and a small expansion reservoir is maintained at all times with the expansion reservoir being integral with and located on the top portion of the radiator and to the side of a radiator filling neck also located thereat. The filling neck is provided with a transparent viewing cap so that the level of liquid coolant can be observed at all times.

Abstract: A hermetically sealed low pressure, low temperature cooling system for internal combustion engines which include a thermostat that operates at a predetermined temperature, typically 195.degree. F. Thermostatic control of engine operation temperature is maintained at or in relatively close proximity to this predetermined temperature thereby eliminating overheating and corrosive deterioration of the cooling system. Free coolant flow between the radiator and a small expansion reservoir is maintained at all times with the expansion reservoir positioned at the elevation of an outlet near the top of the radiator or slightly above this elevation. The system is provided with a transparent viewing cap for the radiator so that the level of liquid coolant can be observed at all times.