Oil Relief Valve
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 for assembly condition and damage, and the relief valve spring for damage and deterioration. Replace the parts if defective.
Relief valve spring:
Free length
73.7 mm (2.902 in)
Installed length
54.7 mm (2.154 in)
Load when installed
93.1 N (9.49 kgf, 20.93 lbf)