Cylinder Leakage Detector

When a cylinder produces a low reading during the compression check, the use of Cylinder Leakage Detector 014-00705 or equivalent will be helpful in pinpointing the exact cause.

The leakage detector is inserted in the spark plug hole, the piston (6108) is brought up to dead center on the compression stroke, and compressed air is admitted.

Once the combustion chamber is pressurized, a special gauge will read the percentage of leakage. Leakage exceeding 20 percent is considered excessive.

While the air pressure is retained in the cylinder, listen for the hiss of escaping air. A leak by the intake valve (6507) will be audible in the throttle body (9E926) . A leak by the exhaust valve (6505) can be heard at the tail pipe. Leakage past the rings will be audible at the crankcase ventilation tube (6758) . If air is passing through a blown head gasket (6051) to an adjacent cylinder, the noise will be evident at the spark plug hole of the cylinder into which the air is leaking. Cracks in the cylinder block (6010) or gasket leakage into the cooling system may be detected by a stream of bubbles in the radiator (8005) .