where is gas tank located on a car
Fuel tank For safety considerations, in modern cars the fuel tank is usually located ahead of the rear axle, out of the crumple zones of the car.
Expansion tank An expansion tank or expansion vessel is a small tank used to protect closed (not open to atmospheric pressure) water heating systems and domestic hot water systems from excessive pressure. The tank is partially filled with air, whose compressibility cushions shock caused by water hammer and absorbs excess water pressure caused by thermal expansion.