Because on Spark plugs your putting a non-compatible metal into a magnesium thread. electrolysis sets up and could weld the plug in the head. j duncan <whocanduncan@xxxxxxxxxxx> wrote: Just curious: why do you recommend anti-seize for a basic tune-up? _________________________________________________________________ Search for grocery stores. Find gratitude. Turn a simple search into something more. http://click4thecause.live.com/search/charity/default.aspx?source=hmemtagline_gratitude&FORM=WLMTAG