Abstract: An apparatus for determining the existence of a head-gasket failure in an engine is provided. The apparatus includes an accumulator in fluid communication with the engine, an engine coolant flow path in fluid communication with the engine and with the accumulator, and a gas flow path fluidly coupled to the accumulator. The apparatus further includes at least one gas analyzer fluidly coupled to the accumulator via the gas flow path that receives a sample gas from the accumulator via the gas flow path to allow the at least one gas analyzer to detect an amount of carbon dioxide in the sample gas.