Caution: All measurements of the cylinder block must be made when the block is positioned on a flat surface.
If the block is mounted on the engine stand, the measurements can be wrong because of distortion.
Inspect the gasket surfaces.
Visually inspect for burrs or damage.
Use an Arkansas hone or a crocus cloth to remove the burrs.
Check the top surface of the block for wear. If fretting damage, scratches, cracks, or corrosion deeper than 0.08 mm [0.003-inch] are present in an area where a head gasket seal ring or a grommet makes contact, the surface must be repaired. There must not be any defect which extends more than 2.41 mm [0.095-inch] from the edge of the coolant passage.
Fretting damage in any other area is acceptable if it does not change the protrusion measurement of the counter-
bore or the cylinder liner.
Refer to the Alternative Repair Manual, Bulletin No. 3379035, for machining instructions.
Use a 610 mm [24 inches] caliper to measure the height of the cylinder block from the main bearing bore outside
diameter to the cylinder head deck surface.
If the height of the block is less than 422.12 mm [16.619 inches], a 0.25 mm [0.010-inch] oversize head gasket
must be used.
The height of the block must not vary more than 0.05 mm [0.002-inch] from end to end of the block. If the block
height is not within specifications, the top surface of the block must be machined or the block must be replaced.
NOTE: If the top surface of the block is machined, the ledge depth of the cylinder liner counterbore must be machined.
Refer to the NH/NT Counterbore Troubleshooting and Repair Manual, Bulletin No. 3810450, or the N14 Trou-
bleshooting and Repair Manual, Bulletin No. 3810456, for detailed instructions.
To inspect the cylinder liner counterbore, refer to the NH/NT Counterbore Troubleshooting and Repair Man-
ual, Bulletin No. 3810450, or the N14 Troubleshooting and Repair Manual, Bulletin No. 3810456, for complete
instructions.
