Spark Plug: Installation

NOTE: The 4.7L 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.

Start the spark plug into the cylinder head by hand to avoid cross threading.
Tighten spark plugs to 27 N.m (20 ft.lbs.). 3.7L & 4.7L.
The 5.7L is equipped with torque critical design spark plugs. Do not exceed 15 ft. lbs. torque. Tighten spark plugs to 18 N.m (13 ft.lbs).
NOTE: 5.7L does not use an o-ring
Before installing ignition coil(s), check condition of coil O-ring and replace as necessary. To aid in coil installation, apply silicone to coil O-ring.
Install ignition coil(s) (Refer to ELECTRICAL/IGNITION CONTROL/IGNITION COIL - INSTALLATION) .