SYS.OK|MANUAL.DB● LIVE
HOMESERVICE MANUALSSUBARU2014FORESTER 2.5I, ENG CD FB25BA, STANDARD TRANSREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT VARIANT/TRIMSECTION 2 (ENGINE MECHANICAL (H4DOTC))CYLINDER BLOCKINSPECTIONPISTON RING
2014 Subaru Forester 2.5i, Eng CD FB25BA, Standard Trans

Piston Ring

2014 Subaru Forester 2.5i, Eng CD FB25BA, Standard TransSECTION Piston Ring
WARNING: This page is about a different variant/trim than selected.
  1. Make sure the piston ring is not broken or damaged.
  2. Using a cylindrical guide, insert the piston ring into the cylinder liner so that they are perpendicular to the cylinder wall, and check the piston ring gap using a thickness gauge. If it is not within the standard, replace the piston ring.
    NOTE:
    • Measurement should be performed at a temperature of 20°C (68°F).
    • Use piston ring with same size as piston when replacing piston ring.

    Piston ring gap: 

    Compression ring (top ring) 

    Standard 

    0.20 - 0.25 mm (0.0079 - 0.0098 in) 

    Compression ring (second ring) 

    Standard 

    0.40 - 0.50 mm (0.0157 - 0.0197 in) 

    Oil ring (upper rail and lower rail) 

    Standard 

    0.10 - 0.35 mm (0.0039 - 0.0138 in) 

    Fig 1: Checking Piston Ring Gap
    G09480624Courtesy of SUBARU OF AMERICA, INC.
  3. Fit the compression ring straight into the piston ring groove, then check the clearance between compression ring and piston with a thickness gauge. If it is not within the standard, replace the compression ring.
    NOTE:
    • Measurement should be performed at a temperature of 20°C (68°F).
    • Before inspecting the clearance, clean the piston ring groove and compression ring.
    • Use compression ring with same size as piston when replacing compression ring.

    Clearance between compression ring and piston: 

    Top ring 

    Standard 

    0.040 - 0.080 mm (0.0016 - 0.0031 in) 

    Second ring 

    Standard 

    0.045 - 0.085 mm (0.0018 - 0.0033 in) 

    Fig 2: Checking Clearance Between Compression Ring And Piston
    G08317252Courtesy of SUBARU OF AMERICA, INC.
RENDER: 1.0x

NO RELATED

Recommended Tools & Savings

Use the Manual With the Right Hardware

Pair factory procedures with proven DIY tools so the instructions are easier to execute.

Affiliate disclosure: We may earn a commission at no extra cost to you.

Shop Manual-Ready ToolsFree Quote CheckQuote Shield Pro

When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.