During engine diagnostics, what does an elevated cylinder leakage test result specifically suggest?

An elevated cylinder leakage test result specifically suggests a loss of compression within that particular cylinder, indicating that combustion gases are escaping from the cylinder more rapidly than they should. A cylinder leakage test measures the percentage of compressed air that leaks from a cylinder when it is pressurized. The cylinder is pressurized with compressed air while the piston is at Top Dead Center (TDC) on the compression stroke, and both intake and exhaust valves are closed. A normal cylinder typically has a leakage rate of only a few percent. An elevated leakage rate, typically above 10-15%, indicates a problem with the cylinder's sealing capabilities. The location of the air leak can provide further clues. Air escaping from the exhaust pipe suggests a leaking exhaust valve. Air escaping from the intake manifold suggests a leaking intake valve. Air escaping from the adjacent cylinder indicates a blown head gasket between the cylinders. Air escaping from the oil filler cap or dipstick tube suggests worn or damaged piston rings or cylinder walls. A hissing sound from the cooling system indicates a leak into the cooling system, possibly due to a cracked cylinder head or block. Therefore, an elevated cylinder leakage test result points to issues such as worn or damaged piston rings, leaky or damaged valves, a blown head gasket, or cracks in the cylinder head or block, all of which reduce engine efficiency and power.