For fast and easy diagnose of blown head gaskets, cracked blockes and cylinder heads. If cylinder head gasket is broken, combustion gas including CO2 gets into cooling system. Reaction fluid in tester chamber reacts with gas in cooling system. If combustin gas is detected reaction fluid will change its colour. The double chamber feature of the leak tester assures a high level accuracy. It seperates alcaline particles present in cooling fluid which can cause false indication.