Spark Plug: Service and Repair

REMOVAL
Each individual spark plug is located under each ignition coil. Each individual ignition coil must be removed to gain access to each spark plug. Refer to Ignition Coil Removal/Installation.

1. Prior to removing spark plug, spray compressed air around base of ignition coil at cylinder head. This will help prevent foreign material from entering combustion chamber.
2. Remove spark plug from cylinder head using a quality socket with a rubber or foam insert. Also check condition of coil O-ring and replace as necessary
3. Inspect spark plug condition. Refer to Spark Plug Conditions.

CLEANING
The plugs may be cleaned using commercially available spark plug cleaning equipment. After cleaning, file center electrode flat with a small point file or jewelers file before adjusting gap.

CAUTION: Never use a motorized wire wheel brush to clean spark plugs. Metallic deposits will remain on spark plug insulator and will cause plug misfire.

INSTALLATION

CAUTION: The 4.7L V-8 engine is equipped with copper core ground electrode spark plugs. They must be replaced with the same type/number spark plug as the original. If another spark plug is substituted, pre-ignition will result.

Special care should be taken when installing spark plugs into the cylinder head spark plug wells. Be sure the plugs do not drop into the plug wells as electrodes can be damaged.

Always tighten spark plugs to the specified torque. Over tightening can cause distortion resulting in a change in the spark plug gap or a cracked porcelain insulator.

1. Start the spark plug into the cylinder head by hand to avoid cross threading.
2. Before installing coil(s), check condition of coil O-ring and replace as necessary. To aid in coil installation, apply silicone to coil o ring
3. Install ignition coil(s). Refer to Ignition Coil Removal/Installation.