5. CLEAN CYLINDER HEAD Using a soft brush and solvent, clean the head. CAUTION: Do not clean the head in a hot tank as this will seriously damage it. 6. CHECK HEAD FOR FLATNESS (a) Using a precision straight edge and feeler gauge, check that neither the head nor manifold surface is warped. (b) Measure warpage at the four sides and diagonally as illustrated. Maximum head surface warpage: 0.10 mm (0.0039 in.) Maximum intake manifold surface warpage: 0.10 mm (0.0039 in.) Maximum exhaust manifold surface warpage: 0.10 mm (0.0039 in.) Maximum camshaft housing surface warpage: 0.10 mm (0.0039 in.) If warpage is greater than specified value, replace the head. 7. INSPECT CYLINDER HEAD FOR CRACKS Using a dye penetrant, check the combustion chamber, intake and exhaust ports, head surface and the top of the head for cracks. If a crack is found, replace the head. 8. CLEAN VALVES Use a gasket scraper to chip any carbon from the valve head. Using a wire brush, clean the valve thoroughly.