The white portion of the spark plug cracked while i was twisting it off and now i cant get the plug out and the 10mm for some reason wont get out either

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    Welcome to Motor Vehicle Maintenance & Repair! What exactly are you working on (year/make/model/engine of the vehicle)? What have you tried to get the spark plug out? Can you take a pic so we can see the condition? I've never experienced a spark plug which is only 10mm ... is this what you really meant to write? Need more information to be able to help you. Apr 22, 2018 at 23:52

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If you have the whole porcelain part of the spark plug and electrode etc, my advice would be to take the car or have it towed to a reputable shop/mechanic so that they can attemp to remove whats left of the plugs head and thread. Otherwise without the various tools garages have you may end up causing more damage to the cylinder head etc.

Unfortunately if the thread is seized in, & the porcelain or head of the spark plug has sheared or broken, then you'll likely need to have the cylinder head removed, so that any broken bits of plug can be removed from the combustion chamber.

If nothing at all has fallen into the combustion chamber.. Some will try and get the plug thread etc out with a slot head screwdriver which I've done myself, however unless the thread is already loosened and this is done correctly, you can easily damage the plug threads in the cylinder head and the tapered seat too.

Even if the thread does come out you must be 100% sure that there's nothing left in the combustion chamber, as any broken bits of spark plug or swarf trapped in there can damage the engine.

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