There is no industry rule requiring every fuel door to sit on the same side. Automakers choose its location based on the vehicle’s overall engineering. Beneath the floor are the fuel tank, exhaust, suspension, wiring, brakes, and structural components.

Engineers must route the filler neck from the outside door to the tank without interfering with heat, crash structures, or a crowded underbody. On one model, the cleanest path may be on the driver’s side. On another, the same manufacturer may choose the opposite side because the exhaust, spare-tire well, or frame rails leave fewer options. Manufacturing also locks much of that decision in place. Moving a fuel door can require new body stampings, different fuel lines, and changes to the assembly process.

That is why two cars from the same brand can have fuel doors on opposite sides. Their platforms, wheelbases, underbody layouts, and structural designs can differ significantly. The driver’s side is not automatically the correct choice. Some vehicles place the filler door on the passenger side simply because that is where the plumbing and surrounding structure fit best. What looks random at a gas station is actually the result of separate engineering decisions.

Fortunately, drivers do not need to memorize every vehicle’s fuel-door location. The dashboard fuel-pump icon usually includes a small triangle or arrow. That mark points toward the side where the filler door is located. Checking it before pulling into a pump can save you from stopping on the wrong side and having to awkwardly reposition the car.

The arrow exists because vehicle designs vary so much. Engineers have to balance packaging, manufacturing, crash protection, fuel-system requirements, heat management, and the existing vehicle platform. A choice that makes perfect sense on one model may be impractical on another, even when both vehicles come from the same company.

So the next time you wonder why one car has its fuel door on the left while another has it on the right, there is no mystery or prank involved. The location is simply where the engineers found the most workable route. You do not need to remember every model. Just look at the little arrow on the dashboard. The fuel door goes where the design allows it to work; the arrow tells you where to find it.