Spac If you clean it well enough, then JB Weld will hold.
I did a repair on my partners V70 (2001) model, after we hit a rock which resulted in a weeping crack to the sump. I removed the oil from the sump, and cleaned the area and lightly sanded (80 grit) the area around the crack. I applied the epoxy weld repair stuff, let it set, and it didn't leak a drop for about 2 months. I ended up replacing the sump (paranoia mainly), but checked the repair, and it was completely solid. It is surprisingly good stuff. Preparation is the key. Good luck with it.