During a cylinder leakage test, hearing air from the exhaust pipe indicates which potential problem?

Hearing air from the exhaust pipe during a cylinder leakage test typically indicates a burned exhaust valve. When an exhaust valve is damaged or not sealing properly, it can allow combustion gases to escape into the exhaust system. This leakage is detectable as air escaping from the exhaust pipe, signifying that the valve is not effectively sealing the combustion chamber during the exhaust stroke.

Other options may suggest different issues. For example, a leaking head gasket might allow air to escape but would be more likely to present symptoms like coolant leaks or bubbles in the radiator, rather than audible air from the exhaust. A clogged exhaust system would lead to back pressure issues rather than air escape. Faulty piston rings would result in a loss of compression but would typically mean air escaping through the valve cover or crankcase rather than the exhaust. Therefore, indicating a burned exhaust valve through audible air from the exhaust pipe is the most accurate interpretation in the context of a cylinder leakage test.