Cylinder Leakage Test

NOTE: Ford does not provide a TDC (Top Dead Center) mark or determination procedure for this engine in this vehicle.
ALLDATA users have reported success using aftermarket tools to determine TDC on this engine.





When a cylinder produces a low reading, the use of a Rotunda Pressurization Kit 014-00705 or equivalent is helpful in pinpointing the exact cause.

With all of the spark plugs removed, the leakage detector is inserted into the spark plug hole. The piston is brought up to top dead center (TDC) 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 past the intake valve will be audible in the throttle body. A leak past the exhaust valve can be heard at the tail pipe. Leakage past the piston rings will be audible at the positive crankcase ventilation (PCV) connection. If air is passing through a blown head gasket into an adjacent cylinder, the noise will be evident at the spark plug hole or the cylinder into which the air is leaking. Cracks in the cylinder block, cylinder head or gasket leakage into the cooling system can be detected by a stream of bubbles in the radiator.