Valve Lifter

WARNING: This page is about a different car, the 2012 Subaru Forester. However, it is still accessible from the selected car via links, so may be relevant.

Check the valve lifter visually.
Measure the outer diameter of valve lifter.
Outer diameter of valve lifter:

34.959 - 34.975 mm (1.3763 - 1.3770 in)

Fig 1: Checking Valve Lifter
Courtesy of SUBARU OF AMERICA, INC.
Measure the inner diameter of valve lifter mating surface on cylinder head.
Inner diameter of valve lifter mating surface:

34.994 - 35.016 mm (1.3777 - 1.3786 in)

Fig 2: Measuring Inner Diameter Of Valve Lifter Mating Surface On Cylinder Head
Courtesy of SUBARU OF AMERICA, INC.
Check the clearance between valve lifter and valve lifter mating surface. The clearance can be determined from the measured value of the valve lifter outer diameter and valve lifter mating surface inner diameter. If it is not within the standard or there is uneven wear in the inner surface, replace the cylinder head.
Clearance between valve lifter and valve lifter mating surface:

Standard

0.019 - 0.057 mm (0.0007 - 0.0022 in)