Spark Plug Installation Guidelines
In modern engines, cylinder heads are usually made of aluminum, and this material expands more than the spark plugs when heated, causing the threads to seize. Therefore, the engine must be completely cold when changing the spark plugs.
Follow these steps to install a spark plug:
Loosen the existing spark plug.
Before removing it, clean any deposits and dirt from the spark plug hole using a brush or, if available, compressed air.
Unscrew the old spark plug.
Remove any large debris from the spark plug hole area.
Hand-tighten the spark plug until it is snug.
Never use spark plugs that have been dropped on a hard surface without being sealed.
Place the specified wrench on the spark plug nut and tighten moderately.