Mack ASET AC, Service Manual

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Page 108
TROUBLESHOOTING
Cylinder Head Coolant Passage
Leak Check — Out of Chassis
Refer to Figure 101.
1. Remove cylinder head from the engine.
2. Fabricate a suitable 3/4-inch thick (19.1 mm)
steel plate and a 1/4-inch (6.4 mm) rubber
gasket. The plate must have cutouts for the
entire combustion chamber. Position plate
and gasket assembly on the underside of
the head and secure with C-clamps, or with
head bolts if the plate has been drilled for
bolts.
3. Use suitable plate and gasket to seal the
water manifold openings. Install an air fitting
onto the plate.
4. Immerse the cylinder head in water. Heat
the water and head to 150
°
F (66
°
C).
5. Apply up to 50 psi (345 kPa) air pressure to
the fitting installed in the plate covering the
water manifold opening. Check for air
bubbles. The formation of air bubbles
indicates that the cylinder head coolant
passages may be leaking.
101
Figure 101 — Cylinder Head Coolant Passage Leak Check (Out of Chassis)
5-111.bk Page 108 Monday, July 10, 2006 2:26 PM