Mack E7, Service Manual

Page: 288 / 303

Page 9-16
200 TROUBLESHOOTING
CYLINDER HEAD OIL PASSAGE LEAK
CHECK — OUT OF CHASSIS
Refer to Figure 9-5.
1. Remove cylinder head from the engine.
2. Install a suitable plug to seal the rocker arm
oil passage at deck side of head. There are
two ways to plug the hole:
앫
Drill and tap the oil passage to accept a
pipe plug.
앫
Insert a suitable rubber plug and clamp
the plug in position with a C-clamp.
3. Install an air fitting in the rocker arm
passage in the top of the head. Use a
discarded rocker arm bracket, preferably
with an oil feed passage. Cut the bracket
through the rocker arm shaft bore parallel to
the mounting surface. Drill and tap the oil
supply passage to accept an air fitting.
4. Bolt the modified bracket, with air fitting, to
the cylinder head over the oil supply
passage.
5. Immerse cylinder head in water and heat to
150°F (66°C).
6. Apply up to 50 psi (345 kPa) air pressure to
air fitting adapter installed in rocker arm oil
passage. Check for air bubbles. The
formation of air bubbles indicates internal
leakage in cylinder head oil passage.
Do not exceed 50 psi (345 kPa). Damage to seals
or cup plugs may result.
Figure 9-5 — Cylinder Head Oil Passage Leak Check (Out of Chassis)
5-101.bk Page 16 Friday, March 17, 2006 11:05 AM