There is no industry rule requiring fuel doors to sit on one particular side. Instead, engineers work around the tank, exhaust, suspension, wiring, brakes, and structural components beneath each vehicle. The filler neck needs a suitable route from the body opening to the tank, avoiding heat and interference with crash structures. Depending on the layout, either side may offer the best fit. Once production is established, relocating the door can mean costly changes to body panels, fuel plumbing, and assembly processes.
That explains why vehicles from the same manufacturer can send drivers to opposite sides of the pump: different platforms create different constraints. Neither side is automatically correct. Fortunately, most vehicles provide a simple reminder beside the dashboard’s fuel-pump symbol. A small arrow or triangle points toward the filler door. Before choosing a pump, check that indicator. One quick glance can prevent an inconvenient maneuver and make an unfamiliar car feel a little less unfamiliar.