Valve Spring Squareness

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.

Set try square along the side of valve spring and rotate the spring. Measure the maximum clearance between the top face of spring and try square.
Limit: Less than 2.2 mm (0.087 in)

Fig 1: Checking Valve Spring Squareness
Courtesy of NISSAN NORTH AMERICA, INC.
If measurement is not within specifications, replace the valve spring.