Mine leaked and I sealed it, perfect for 9 years.
We tried to weld it up but we could not get everything clean enough and the split kept moving up the seam.
The sealer is a silver color, so when you do an oil change you can see the tank is clean as a whistle.
The sealer smooths over the crease between the panels, locking in any old garbage that you think you cleaned out by swishing solvent.
Made for gasoline, the oil certainly won't be breaking it down. At this point I like the benefits enough that I would seal a non leaking tank.
Lee