The purpose of a combustion leak tester is to determine the amount of combustion gases in the engine coolant. A hydrogen gas leak detector’s primary purpose is to identify any leaks from an engine’s combustion compartment (internal combustion) to the cooling water jacket adjacent to the combustion compartment. What is a combustion leak tester used for? Nowadays, most vehicles, including cars and trucks, have water-cooled internal combustion engines, and combustion leakage into the cooling system can be exceedingly harmful since exhaust gases react with coolant to generate corrosive acids. All