Spark Plug: Inspection

Disconnect the spark plug cable from the spark plug.
NOTE: Pull on the spark plug cable boot when removing the spark plug cable, not the cable, as it may be damaged.

Fig 1: Removing Spark Plug Cables
Courtesy of HYUNDAI MOTOR CO.
Using the spark plug wrench, remove all of the spark plugs from the cylinder head.
NOTE: Take care not to allow contaminants to enter through the spark plug holes.
Check spark plugs for the following:
1. Broken insulator
2. Worn electrode
3. Carbon deposits
4. Damaged or broken gasket
5. Condition of the porcelain insulator at the tip of the spark plug
  
  Fig 2: Inspecting Spark Plug
  Courtesy of HYUNDAI MOTOR CO.
Check the spark plug gap using a wire gap gauge, and adjust if necessary.
Standard value

Spark plug gap: 1.0 ~ 1.1 mm (0.039 ~ 0.043 in.)

Fig 3: Checking Spark Plug Gap
Courtesy of HYUNDAI MOTOR CO.
Re-insert the spark plug and tighten to the specified torque. If it is over torqued, damage to the threaded portion of cylinder head may result.
Tightening torque

Spark plug: 20 ~ 30Nm (200 ~ 300kg.cm, 15 ~ 22 lb. ft)

NOTE: When replacing the spark plug, use the genuine parts which have resistance.