Thats a common place/way for an an
oil pan to fail---
oil pans will
oil can---and the stress point is at the weld line where two flat sheets come together at 090*and are welded---especially with alum--there are so many different alloys of sheet stock, so many different welding rod alloys and then add in the welding technique and you have a sure to happen failure--just depends on how long it'll take