When one cylinder has a lower compression pressure and higher exhaust gas temperature than any of the other engine cylinders, which of the conditions listed will be indicated?

Correct Answer: Option C — Leaky exhaust valve

A leaky exhaust valve fails to seal during the compression and power strokes, causing a loss of compression pressure and incomplete combustion. The escaping burning gases overheat the exhaust valve and local manifold area, driving exhaust pyrometer readings higher than neighboring cylinders.