Valve Lifter

WARNING: This page is about a different car, the 2013 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:

Standard

34.959 - 34.975 mm (1.3763 - 1.3770 in)

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

Standard

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 checked by measuring the outer diameter of valve lifter and the inner diameter of valve lifter. If it exceeds the standard or offset wear occurs, replace the cylinder head.
Valve lifter and valve lifter mating surface clearance:

Standard

0.019 - 0.057 mm (0.0007 - 0.0022 in)