Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
2021 Subaru Outback BaseFACTORY OEM SERVICE PROCEDURE
Piston Ring
WARNING: This page is about a different variant/trim than selected.
| Closed gap | mm (in) | Compression ring | Top ring | Standard | 0.22 - 0.27 (0.0087 - 0.0106) |
| Second ring | Standard | 0.35 - 0.45 (0.0138 - 0.0177) | |||
| Oil ring (Upper rail and lower rail) | Standard | 0.10 - 0.35 (0.0039 - 0.0138) | |||
| Clearance between compression ring and piston | mm (in) | Top ring | Standard | 0.040 - 0.080 (0.0016 - 0.0031) | |
| Second ring | Standard | 0.045 - 0.085 (0.0018 - 0.0034) | |||
Factory Service Tools
Use the Manual With the Right Hardware
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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.