What does a compression test measure in an engine?

A compression test measures the ability of the engine to seal and maintain pressure within its cylinders. This assessment is critical because it evaluates the effectiveness of components such as piston rings, cylinder walls, and the cylinder head and its gaskets. When these parts are functioning properly, they create a seal that allows for optimal compression during the engine's compression stroke, which is vital for efficient combustion and overall engine performance.

Low compression readings can indicate potential issues such as worn piston rings, damaged cylinders, or valve problems, all of which can reduce engine performance and efficiency. By performing a compression test, technicians can diagnose problems that could lead to more severe engine damage if left unaddressed. Thus, this test provides valuable insights into the engine's mechanical health and its ability to operate effectively.