What is the purpose of performing a cylinder leakage test on a diesel engine, and what does it indicate about engine condition?

The purpose of performing a cylinder leakage test on a diesel engine is to assess the condition of the cylinder's sealing capabilities, which directly relates to the engine's overall health and efficiency. The test measures the amount of compressed air that leaks out of a cylinder when it is pressurized. Excessive leakage indicates problems with the cylinder's components, such as the piston rings, valves, or cylinder head gasket. A cylinder leakage test involves bringing the piston of the cylinder being tested to top dead center (TDC) on the compression stroke and then injecting compressed air into the cylinder through the spark plug or injector hole. A cylinder leakage tester has tw....