Automotive what is a bleeddown test?

A bleeddown test, also known as a cylinder leakage test, is an automotive diagnostic procedure used to assess the condition of an engine's internal components. During the test, compressed air is introduced into a cylinder at top dead center, and the rate at which the air escapes is measured. This helps identify issues such as worn piston rings, damaged valves, or head gasket leaks, as the escaping air can be heard or felt from various engine parts. It provides insight into the engine's overall health and potential areas that may require repair.