Valve Lifter

WARNING: This page is about a different car, the 2013 Nissan Armada. However, it is still accessible from the selected car via links, so may be relevant.

Check if the surface of the valve lifter has any wear or cracks.

If any damage is found, replace the valve lifter.
Select the thickness of the head so that the valve clearance is within the standard when replacing. Refer to "VALVE CLEARANCE ".

Fig 1: Locating Valve Lifter Surface
Courtesy of NISSAN NORTH AMERICA, INC.