Spark Plug: Installation
CAUTION:
The standard 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.
CAUTION:
If equipped with a 4.7L H.O. (High-Output) engine, never substitute the original platinum tipped spark plug with a different type/part number. Serious engine damage may result.
Special care should be taken when installing spark plugs into cylinder head spark plug wells. Be sure plugs do not drop into plug wells as ground straps may be bent resulting in a change in plug gap, or electrodes can be damaged.
Always tighten spark plugs to specified torque. Over tightening can cause distortion resulting in a change in spark plug gap or a cracked porcelain insulator.
- Start spark plug into cylinder head by hand to avoid cross threading.
- 4.0L 6-Cylinder Engine: Tighten spark plugs to 35-41 N.m (26-30 ft. lbs.) torque.
- 4.7L V-8 Engine: Tighten spark plugs to 27 N.m (20 ft. lbs.) torque.
- 4.7L V-8 Engine: 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.
- Install ignition coil(s). Refer to INSTALLATION .