Rodeo LS 4WD V6-3.2L (1998)
-
Excessive gap means that the air space between the center and the side electrodes at the bottom of the spark plug is too wide for consistent firing.
This may be due to improper gap adjustment or to excessive wear of the electrode during use. A check of the gap size and comparison to the gap
specified for the vehicle will tell if the gap is too wide. A spark plug gap that is too small may cause an unstable idle condition. Excessive gap
wear can be an indication of continuous operation at high speeds or with engine loads, causing the spark to run too hot. Another possible cause is
an excessively lean fuel mixture.
-
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.
Overtightening 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 regapping, 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.
-
A broken or cracked lower insulator tip (around the center electrode) may result from damage during regapping or from "heat shock" (spark plug
suddenly operating too hot).
-
Damage during re-gapping can happen if the gapping tool is pushed against the center electrode or the insulator around it, causing the insulator to
crack. When re-gapping a spark plug, make the adjustment by bending only the ground side terminal, keeping the tool clear of other parts.
-
"Heat shock" breakage in the lower insulator tip generally occurs during several engine operating conditions (high speeds or heavy loading) and
may be caused by over-advanced timing or low grade fuels. Heat shock refers to a rapid increase in the tip temperature that causes the insulator
material to crack.
-
Spark plugs with less than the recommended amount of service can sometimes be cleaned and re-gapped, then returned to service. However, if
there is any doubt about the serviceability of a spark plug, replace it. Spark plugs with cracked or broken insulators should always be replaced.
