Page 74
TROUBLESHOOTING
Cylinder Head Oil Passage Leak
Check — Out of Chassis
Refer to Figure 65.
1. Remove the cylinder head from the engine.
2. Install a suitable plug to seal the rocker arm
oil passage at deck side of the head. There
are two ways to plug the hole:
r
Drill and tap the oil passage to accept a
pipe plug.
r
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 with an oil
feed passage. Cut the bracket through the
rocker arm shaft bore parallel to the
mounting base 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 the cylinder head in water. Heat the
water and cylinder head to 150
°
F (66
°
C).
6. Apply up to 50 psi (345 kPa) air pressure to
the air fitting adapter installed in the rocker
arm oil passage. Check for air bubbles. The
formation of air bubbles indicates internal
leakage between the cylinder head oil
passage and the water jacket.
Do not exceed 50 psi (345 kPa). Damage to seals
or cup plugs may result.
65
Figure 65 — Cylinder Head Oil Passage Leak Check (Out of Chassis)
1. Modified Bracket with Air Fitting
2. Plug (Pipe or Rubber)
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