ENGINE,  FUEL,  EXHAUST  AND  COOLING 4-4. Cylinder  Head  Assembly  with DISASSEMBLY/CLEANING/INSPECTION TM  10-3930-643-34 TROUBLESHOOTING  AND  MAINTENANCE. Valves. (Sheet 7 of 18) 17. 18. 19. 20. Attach fitting, pressure gage and hose to thermostat housing plate. Run hot water into cylinder head (6) at 25 psi. Observe cylinder head (6) for leakage at injection nozzle sleeve flanges, upper deck, lower deck, ports and seat insert areas. Inspect lower deck for flatness. Use a straight edge long enough to span both length and width of cylinder head (6). Follow  checking  pattern shown. Insert feeler gage under each point shown. NOTE Cylinder head must be replaced if 0.003 inch feeler gage can be inserted under straight edge across length or width. Sudden changes  in contour such as scratches, gouges, etc., must not exceed 0.002 inches in depth. Remove and discard six sleeves (15) with slide hammer and nozzle sleeve puller adapter. Go to sheet 8 4-35