Weak area. Someone may of reinforced OR repaired. Welds passenger and driver's side ? front and rear? Beads laying like a roll of times or nasty scar.
Sort of joking, but reason I ask, uniform work may lead to some indication of "beefing" it up. Single nasty " scar" might point to repair. Just speculating having no knowledge of your car's prior use. Correct in assuming no leaks?
Post a pic, probably get a few answers ASAP.
