 The fluid is creeping up the dipstick tube. I failed to ask you that question, but I'm betting it is. That it's creeping up the dipstick tube, and this will relieve pressure on that. Because the dipstick tube, I should explain, on a 57 Chevy, goes down into the sump. It goes down into an area that's wet, and it can't ever relieve the pressure. It's just self-pressurizing, pushing the fluid out the tube.