What do you do when you’re removing a glow plug in your Sprinter and the darn thing breaks off because it’s seized in the cylinder head? This happens as often as it doesn’t.
You can try anything that comes to mind, and desperately search for YouTube videos, and ultimately you will find that either it’s futile, or like as not you’ve drilled into the cylinder head, or the piston, and at that point the situation “just got real.”
We’ve spent $5,000 on special tools for just this purpose. It’s quite a process, but we’ve extracted countless seized / broken glow plugs, and so far, we haven’t had to remove a single cylinder head. This saves about $3,000 in repairs.