If the spark plug doesn't need to be replaced, return it to the spark plug bore. If it does need to be replaced, use a new one.

Use of Anti-Seize on the thread of spark plug is highly recommended to ensure threads don't get damaged while tightening.

Use a ratchet, extension, and 5/8 inch socket to tighten the spark plug by turning clockwise. Use your hand to tighten as well.

If a torque wrench is available, tighten to 13 ft-lbs.

Repeat Steps 10-13 for the three remaining spark plugs.