What does a cylinder leak down gauge measure?

A cylinder leak down gauge is specifically designed to assess how well the cylinders in an engine are sealed. This tool works by pressurizing each cylinder and then measuring the amount of air that escapes from it. A high level of leakage indicates that there may be problems such as worn piston rings, damaged valves, or issues with the cylinder head.

Measuring the sealing efficiency of cylinders is crucial as it directly impacts engine performance, efficiency, and overall health. If the cylinders are not sealing properly, it can lead to poor compression, which can affect the engine's ability to generate power. This tool provides valuable diagnostic information to technicians and mechanics, allowing them to identify and address issues before they lead to more significant damage or loss of performance.

The other options, while related to engine performance, do not pertain to the function of a cylinder leak down gauge and thus are not relevant to its purpose.