2.5 L (Non-Turbo) Model

Remove the intake duct and intake chamber.
Remove the battery.
Disconnect the spark plug cord.
Remove the spark plug with a spark plug socket.

Fig 1: Removing Spark Plug With Spark Plug Socket
Courtesy of SUBARU OF AMERICA, INC.
Tighten the new spark plug lightly with hand, and then secure with a spark plug socket to the specified torque.

Recommended spark plug:

NGK: PFR5B-11

Tightening torque:

21 N.m (2.1 kgf-m, 15.2 ft-lb)

NOTE:

Be sure to place the gasket between the cylinder head and spark plug.
If the torque wrench is not available, tighten the spark plug until gasket contacts cylinder head; then tighten further 1/4 to 1/2 turns.