Tapping thread in spark plug hole

Fig 1: Identifying Tap, Reamer, And Steering

Courtesy of VOLVO CARS OF NORTH AMERICA.

Use combination tap 998 5823-5 and thread repair inserts for spark plug thread M14x1.25 .

NOTE:

Do not drill out spark plug threads.

Combined tap

A: Tap.

B: Reamer.

C: Steering.