03-oo-9
Engine-Service
03-00-9
SERVICE PROCEDURES (Continued)
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 heard in the throttle body {9E926). A
leak by the exhaust valve {6505) can be heard at the
tailpipe. Leakage past the piston rings will be audible
at the positive crankcase ventilation {PCV)
connection. Hair is passing through a blown head
gasket {605 1) 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 blocks {6010)
or gasket leakage into the cooling system may be
detected by a stream of bubbles in the radiator
{8005).
ROTUNDA ENGINE CYLINDER LEAK
DETECTION/ AIR P RESS URIZ ATION KIT
014-00705
A23313·B
Oil Leak and Valve Guide Seal Test
The cylinder leakage detector tests for engine oil
leaks and checks the valve stem seals {657 1 ) for
leakage.
1 . Plug all crankcase openings except the one used
for connecting the leakage detector.
2. Connect the detector to a crankcase opening {an
oil level indicator tube {6754) is convenient).
Adjust the air pressure to approximately 34 kPa
{5 psi).
3.
Using a solution of liquid soap and water, brush
the solution along the gasket sealing surfaces
and bearing seals. Look for bubbles or foam.
4. Remove the spark plugs { 1 2405) and rotate the
crankshaft {6303) slowly with a wrench. Check
for large amounts of air escaping into the
cylinders as each intake valve {6507) and
exhaust valve {6505) opens.
5. The spark plugs on the leaking cylinders will
probably show deposits of burned oil.
Intake Manifold Vacuum Test
Bring the engine to normal operating temperature.
Connect Rotunda Vacuum
I
Pressure Tester
1 64-R0253 or equivalent to the intake manifold
{9424). Run the engine at the specified idle speed.
The vacuum gauge should read between 51· 7 4 kPa
{ 15-22 in-Hg) depending upon the engine condition and
the altitude at which the test is performed. Subtract
4.0 1 93 kPa { 1 in-Hg) from the specified reading for
every 304.8 m { 1
,
000
feet) of elevation above sea
level.
The reading should be quite steady. H necessary,
adjust the gauge damper control {where used) if the
needle is fluttering rapidly. Adjust damper until needle
moves easily without excessive flutter.
Vacuum Gauge Readings-Interpretation
A careful study of the vacuum gauge reading while the
engine is idling will help pinpoint trouble areas. Always
conduct other appropriate tests before arriving at a
final diagnostic decision. Vacuum gauge readings,
although helpful, must be interpreted carefully.
Most vacuum gauges have a normal band indicated on
the gauge face.
ROTUNDA VACUUM/PRESSURE TESTER
164-R0253
AA0197-A
1997 Thunderbird, Cougar July 1 996
