Which tool is used to measure engine compression?

The tool used to measure engine compression is a compression gauge. This device provides a direct reading of the pressure created in the engine's cylinders during the compression stroke. By screwing the gauge into the spark plug hole, mechanics can crank the engine to see how much pressure each cylinder can produce. This measurement is crucial for diagnosing engine health, as low compression can indicate problems such as worn piston rings, damaged valves, or head gasket failure.

In contrast, a torque wrench is primarily used for applying a specific amount of torque to fasteners, a vacuum gauge measures intake manifold vacuum to assess engine performance rather than compression, and a multimeter is used for measuring electrical properties such as voltage, current, and resistance, not pressure. Each of these tools serves a distinct purpose and is critical in mechanic work, but for measuring engine compression specifically, the compression gauge is the appropriate choice.