A cylinder leakage tester is a precision automotive diagnostic tool used to measure the amount of air leakage in an engine cylinder and identify internal engine condition issues. It works by introducing compressed air into the cylinder and measuring the percentage of pressure loss, helping detect problems such as worn piston rings, damaged valves, head gasket leaks, or cylinder wall wear. The tool typically includes a pressure gauge, regulator, hoses, and adapters for different spark plug sizes. It is widely used in automotive workshops, engine rebuilding, and maintenance services for both petrol and diesel engines. The cylinder leak-down tester provides accurate diagnostic results, helping technicians assess engine health, improve performance, and plan necessary repairs efficiently.