Wow all these day's and know one has used the correct terms.
You broke the stud off. You well need to find a good repair shop and hopefully have them use a easy out to remove the rest of the stud.
They may need to put a insert in there for the new stud.
I guessing you didn't use any PB Blaster before you did this.
178,000+ miles, 5/20/12 new ej257 short block, 8/20/11 installed VF52 turbo, @20.8psi, 280whp, 300ftlbs. CHECK your oil, these cars use it.
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