With some cars, people remove the inspection cover from below and put a wooden wedge
in the teeth to be kinder to the flywheel. In the absence of a powerful impact wrench,
Wd40 on the bolt plus a sudden kick to a long breaker bar/socket will break it loose.
Next time, pm me. I can break it loose with my impact wrench, and retighten it for your drive home, where you can remove it humanely. -Bob