I'm getting ready to do spark plugs, so just out of curiosity I decided to peek inside a spark plug hole to see if they are the original spark plugs. Turns out they have a "P" marking on them. I believe the Car Care Nut mentioned if there's some kind of marking on the top of the plug it's probably an original one. If so, what are some tips to get these spark plugs out without breaking them? Should I spray some penetrating fluid before trying to wrench them out? I would imagine after 18 years and 150k+ miles that they would be pretty stuck.


Spark plug with a P

 

Don't do anything special just remove them. Penetrating oil won't do anything spark plugs have a tight seal via crush washer oil will never get past it. Exception is if the plug is loosened but is coming out hard, spray penetrating oil 10-15 times over the course of a few hours.

 

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