200 TROUBLESHOOTING

CYLINDER HEAD COOLANT PASSAGE LEAK CHECK — OUT OF CHASSIS

Refer to Figure 9-6.

1.Remove cylinder head from 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 underside of head and secure with C-clamps.

3.Use suitable plate and gasket to seal water manifold openings. Install an air fitting onto the plate.

4.Immerse cylinder head in water. Heat 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 cylinder head coolant passages may be leaking.

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