What does a compression gauge measure in an engine?

A compression gauge measures the pressure inside an engine's cylinder when the piston is at the top of its compression stroke. This pressure is typically expressed in pounds per square inch (PSI). The gauge provides valuable information about the engine’s overall health, as appropriate compression levels are necessary for effective operation. If the compression is too low, it can indicate potential issues such as worn piston rings, valve problems, or a blown head gasket, all of which may affect the engine’s performance and efficiency negatively. The use of a compression gauge is essential for diagnosing engine problems and ensuring it runs optimally.