CAUTION: If lubricant is spilt over the exhaust pipe, wipe it off with cloth to avoid emission of smoke or causing a fire.

Before installing front oxygen (A/F) sensor, apply anti-seize compound only to the threaded portion of front oxygen (A/F) sensor to make the next removal easier.
CAUTION: Never apply anti-seize compound to the protector of front oxygen (A/F) sensor.

Anti-seize compound:

NEVER-SEEZ NSN, JET LUBE SS-30 or equivalent
Install the front oxygen (A/F) sensor.
Tightening torque:

30 N.m (3.1 kgf-m, 22.1 ft-lb)
Secure the front oxygen (A/F) sensor harness to the water pump cover using clip (B), and connect the front oxygen (A/F) sensor connector (A) to the engine harness.

Fig 1: Identifying Front Oxygen (A/F) Sensor Connector And Clip
Courtesy of SUBARU OF AMERICA, INC.
Install the undercover. < Ref. to INSTALLATION , Front Under Cover. >
Lower the vehicle.
Install the radiator main fan & fan motor assembly. < Ref. to INSTALLATION , Radiator Main Fan and Fan Motor. >
Connect the ground terminal to battery sensor. < Ref. to BATTERY , NOTE, Note. >

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.

Safety Warning

Front Oxygen (A/F) Sensor: Installation