Hombre S Regular Cab 4WD V6-4.3L (1999)
Low or high spark plug installation torque or improper seating can result in the spark plug running too hot and can cause excessive center electrode wear.
The plug and the cylinder head seats must be in good contact for proper heat transfer and spark plug cooling. Dirty or damaged threads in the head or on
the spark plug can keep it from seating even though the proper torque is applied. Once spark plugs are properly seated, tighten them to the torque shown
in the Specifications Table. Low torque may result in poor contact of the seats due to a loose spark plug. Over tightening may cause the spark plug shell
to be stretched and will result in poor contact between the seats. In extreme cases, exhaust blow-by and damage beyond simple gap wear may occur.
Cracked or broken insulators may be the result of improper installation, damage during spark plug re-gapping, or heat shock to the insulator material.
Upper insulators can be broken when a poorly fitting tool is used during installation or removal, when the spark plug is hit from the outside, or is
dropped on a hard surface. Cracks in the upper insulator may be inside the shell and not visible. Also, the breakage may not cause problems until oil or
moisture penetrates the crack later.
