It's some pretty good stuff. Once it cures, it takes the same kind of efforts to reshape it as you would expect from metal (files, powersanding, grinding, etc). Since the oil pan isn't subjected to high loads, it would probably do the trick as long as you can glue the pieces back together well enough to not effect the gasket surface's ability to make a seal with the bottom of the block. I've repaired a cast aluminum auto oil pan with the stuff (daughter ran the pan into a parking curb).