Piston Ring

WARNING: This page is about a different car, the 2004 Subaru Outback, 2004 Subaru Legacy, and 2004 Subaru Baja. However, it is still accessible from the selected car via links, so may be relevant.

If piston ring is broken, damaged, or worn, or if its tension is insufficient, or when the piston is replaced, replace piston ring with a new one of the same size as the piston.
NOTE:
- Marks are shown on the end of the top and second rings. When installing the rings to the piston, face this mark upward.
- Oil ring consists of upper rail, expander and lower rail. When installing on piston, be careful of each rail's direction.
Fig 1: Checking Piston Ring If Broken, Damaged Or Worn
Courtesy of SUBARU OF AMERICA, INC.
Clean piston ring grove and piston ring.
Squarely place piston ring and oil ring in cylinder, and measure the piston ring gap with a thickness gauge.

Fig 2: Piston Ring Gap Specification Chart
Courtesy of SUBARU OF AMERICA, INC.

Fig 3: Measuring Piston Ring Gap
Courtesy of SUBARU OF AMERICA, INC.
Measure the clearance between piston ring and piston ring groove with a thickness gauge.

Fig 4: Piston Ring & Piston Ring Groove Clearance Specification Chart
Courtesy of SUBARU OF AMERICA, INC.

Fig 5: Measuring Clearance Between Piston Ring & Piston Ring Groove
Courtesy of SUBARU OF AMERICA, INC.