Gas in coolant diagnostics for internal combustion engine

摘要

A measurement of the quantity of gas entering or within the coolant of an internal combustion engine cooling system, is made with the engine running, preferably at high idle speed, and a test is performed to ensure that the thermostat is open, whereby it is known that coolant is circulating through the entire cooling system, by providing a radiator cap connected to an orifice of a known size that will allow gas to escape from the cooling system and measuring substantially the pressure differential across the orifice, such as by measuring the pressure on the radiator side of the orifice with respect to atmospheric pressure.