This specialized diagnostic tool is employed to assess the integrity of an engine’s cylinders. It functions by introducing pressurized air into a cylinder while the piston is at top dead center on its compression stroke. The rate at which the pressure decreases indicates the extent of leakage past the piston rings, valves, or head gasket. For example, a rapid pressure drop suggests significant leakage, potentially signaling worn piston rings or a faulty valve seal.
Utilizing this device offers numerous advantages in engine diagnostics. Identifying the source of compression loss allows for targeted repairs, avoiding unnecessary component replacement. Accurate assessment can prevent catastrophic engine failure and extend the operational life of a vehicle. Historically, mechanics relied on less precise methods for assessing cylinder condition; the advent of this instrument provided a more reliable and quantitative approach.