I tried changing my spark plugs today and had 6 out of 8 of them snap off in the head. I bought an extraction kit but the diode is still stuck deep in the ceramic and will not push past the diode stuck in the middle. The top of the 2 piece spark plug came out with the rest of it remaining in the head. Any suggestions are welcome. Thank you.

 

damn that sucks. did you get the Lisle tool or a knock off, JW. I had the Lisle tool on hand when I changed mine out at 34k but didn't need it. are you sure your using the tool properly? I only ask and not trying to down you or be a dick. the step for pressing the porcelain and diode thru the bottom part is pretty straight forward and usually isn't difficult. the porcelain and diode get either pushed thru the stirrup or break apart around it. that also adds the step of using thin tubing on your shop vac to get as much of that out of the cylinder as you can. step back and take a break, you'll get em out. good luck

 

The lisle tool is the better one out there. There is another one made by OTC I think but it's pretty much the same as the Lisle one. And, I think the other part stuck in the head besides the porcelain is the electrode, not diode. Spark plugs don't have diodes, alternators do.

Anyways, this video shows you how to handle the stuck electrode so you can get the actual removal tool into the ceramic (cliff notes, you drill it out with one of the tool accessories).