Valve Seat Contact

WARNING: This page is about a different car, the 2019 Nissan NV3500 HD, 2019 Nissan NV2500 HD, and 2019 Nissan NV1500. However, it is still accessible from the selected car via links, so may be relevant.

After confirming that the dimensions of valve guides and valves are within the specifications, perform this procedure.

Courtesy of NISSAN NORTH AMERICA, INC.
Apply prussian blue (or white lead) onto contacting surface of valve seat to check the condition of the valve contact on the surface.
Check if the contact area band is continuous all around the circumference.
If not, grind to adjust valve fitting and check again. If the contacting surface still has "NG" conditions even after the re-check, replace valve seat.