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 WRX STIFACTORY OEM SERVICE PROCEDURE
Intake Side
- Apply liquid gasket to the two bolts securing oil return cover.
Liquid gasket:
THREE BOND 1324 (Part No. 004403042) or equivalent
- Install the oil return cover.NOTE: Use a new gasket.
Tightening torque:
9 N.m (0.9 kgf-m, 6.6 ft-lb)
- Install the oil flow control solenoid valve.
Tightening torque:
6.4 N.m (0.7 kgf-m, 4.7 ft-lb)
- Install the intake manifold. Refer to FUEL INJECTION (FUEL SYSTEMS) (STI)>INTAKE MANIFOLD>INSTALLATION .
- Connect the battery ground terminal.
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.