Cylinder Block Distortion

WARNING: This page is about a different car, the 2004 Nissan Titan. However, it is still accessible from the selected car via links, so may be relevant.

Using a scraper, remove gasket on the cylinder block surface, and also remove oil, scale, carbon, or other contamination.
CAUTION: Be careful not to allow gasket flakes to enter the engine oil or engine coolant passages.
Using a suitable tool, measure the distortion on the block upper face at some different points in 6 directions.
1. Standard : 0.03 mm (0.0012 in)
2. Limit : 0.1 mm (0.004 in)
If out of the distortion limit, replace the cylinder block.

Fig 1: Checking Cylinder Block Distortion
Courtesy of NISSAN MOTOR CO., U.S.A.