Cylinder Block Distortion

Using a scraper, remove gasket on the cylinder block surface, and also remove engine oil, scale, carbon, or other contamination.
CAUTION:
Be careful not to allow gasket flakes to enter engine oil or engine coolant passages.
Measure the distortion on the cylinder block upper face at some different points in six directions (C), (D), (E), (F), (G), and (H) with a straightedge (A) and a feeler gauge (B).

Fig 1: Measuring Distortion On Cylinder Block Upper Face Using Straightedge And Feeler Gauge
Courtesy of NISSAN NORTH AMERICA, INC.

Limit : Refer to CYLINDER BLOCK .
If it exceeds the limit, replace cylinder block.