Villager V6-181 3.0L SOHC VIN 1 EFI (1997)
Compression Check: Testing and Inspection
Cylinder Leakage Test
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.
