The Buick Regal's fuel tank is located on the right side of the rear, a design distinction from other models.

The Regal lacks a dedicated fuel cap opening button; instead, access is controlled by the central locking system. To refuel, the user should park the vehicle safely and shut off the engine, then unlock the central control system on the center console. Once unlocked, the fuel cap can be opened with a simple press.

In earlier Regal models, the fuel cap opening employed a traditional pull-type design, typically located on the floor mat below the driver's seat to the left. This design made refueling more convenient for the driver.

In terms of material, modern car fuel tanks are primarily divided into two types: metal and engineering plastic. Metal fuel tanks are typically made of iron or other metals and offer a more robust structure, while engineering plastic tanks are widely used due to their simplified production process.

The fuel tank plays a vital role in the vehicle's fuel system. It not only stores fuel but also performs functions such as heat dissipation, bubble separation, and impurity precipitation, ensuring stable operation of the fuel system. Fuel tanks are typically equipped with auxiliary equipment such as coolers, heaters, air filters, and level gauges to ensure the proper operation of the fuel system.

Structurally, fuel tanks can be categorized as either open or closed. Open tanks maintain a fluid level open to the atmosphere and are equipped with air filters to prevent the ingress of impurities. Closed tanks, on the other hand, are commonly used for pressure tanks and are filled with a certain pressure of inert gas to maintain stable oil pressure.