Danny G. wrote in article
...

"semidemiurge" wrote in message
ups.com...
My mechanic broke off a sparkplug trying to remove it from the engine
on my 4runner and I am trying to research possible solutions. It
broke off halfway down the threads, so that half of the bottom metal
part is still in the engine head. I was thinking using and easyoff
extractor but worry about metal pieces includint the electrode tip
falling into the cylinder. Anyone have ideas or experience with this?
thanks, rick



Something is wrong with that story.

Put a old plug in your bench vise and try to do that
with a hammer and chisel to see what I mean.
Drilling or even beating out the center of a plug when
it's installed would be a good trick. Even in a vice its
real tuff.


GL
Dan




The situation as the OP described it is quite common.....and the often DO
break right at the top of the threads.

Steel spark plugs in aluminum heads can create some electrolytic activity.

100,000 mile plug change intervals simply give this activity longer to do
its job.

Stop by virtually ANY professional automotive machine shop, and there's a
good chance that there is a head or two that have been dropped off and
sitting in the "To-Do" pile, awaiting a spark plug threadectomy.