The Block Tester is a used to detect the presence of exhaust gases in an engine's cooling system, typically caused by a blown head gasket or cracked head or block. It comes complete with enough fluid to conduct 16 tests. There are no additional tools needed, and no need to tap into an engine vacuum source. Works with virtually any liquid-cooled internal combustion engine or generator with a closed cooling system including: gasoline, diesel, propane, natural gas and other alternative fuels. Large, single-chamber design provides greater accuracy and uses less test fluid.