Cylinder Leakage Tester ·

• Uses: The cylinder leakage tester is used to measure the sealing performance of automobile engine cylinders and determine if they are within an acceptable leakage range. It can also analyze and identify the location and cause of any leakage for troubleshooting purposes.

• · Principle: The testing principle involves injecting a certain amount of compressed air into the cylinder while the engine is static and the piston is at top dead center. The time it takes for the air pressure to drop to a specified value reflects the magnitude of the leakage. A shorter time indicates a larger leakage, while a longer time indicates a smaller leakage. By continuously supplying the cylinder with compressed air at a constant pressure, the main area causing the leakage can be determined, allowing for targeted engine maintenance.
• · Instrument Structure: The instrument consists of a pressure regulator, intake pressure gauge, measurement pressure gauge, air duct, quick-change connector, and other components.

· Main Technical Parameters:

• Pressure Measurement Range: 0-40psi
• Intake Pressure Range: 50psi-120psi
• Working Air Source Pressure: 10-40psi

Instructions:

1. Remove all spark plugs from the engine and rotate the crankshaft using a hand crank to position the piston at top dead center. Engage the parking brake and shift to neutral to prevent the compressed air from moving the piston.
2. Screw the air supply connector onto the first cylinder at top dead center. Connect one end of the air duct with a quick-change connector to the output end of the measuring instrument, and connect the compressed air source to the input end of the testing instrument. Close the pressure regulating valve of the instrument (rotate the knob out when in use).
3. Prepare a stopwatch, open the pressure regulating valve, adjust the dial gauge pointer to zero, close the intake port, and simultaneously start the stopwatch. Record the holding time and observe the changes in the measurement pressure gauge. When the gauge pressure drops to 60%, stop the stopwatch and record the time it takes for the pressure to drop from zero to 60%. By comparing this time with similar engines, the extent of cylinder leakage can be diagnosed. The longer the holding time, the better the cylinder sealing; if the holding time is very short, it indicates severe cylinder leakage and repair is necessary. For convenience, test each cylinder in the firing order sequence. One cylinder can be tested with each half rotation (180°) of the crankshaft.
4. Determining the leakage location: Start the compressed air compressor and supply air to the cylinder at top dead center. Use the pressure regulating valve to control the pressure at around 40psi, carefully listen for any air leakage sound, and determine the location of the cylinder leakage. If air leakage is heard at the intake manifold, it indicates that the intake valve is not sealing properly; if leakage is heard at the exhaust pipe or muffler outlet, it indicates that the exhaust valve is not sealing properly; if slight air leakage is heard at the oil filler cap, it is considered normal; if a significant sound and airflow can be felt, it indicates serious leakage, suggesting that the piston-cylinder clearance is not sealed properly; if bubbles are seen rising from the radiator water when air is supplied, it indicates a blown head gasket, resulting in communication between the cylinder and water jacket; if leakage sound is heard at the adjacent cylinders spark plug port, it indicates that the head gasket between the two cylinders has been blown and causing compression leakage.