A self-adjustable valve or flow control device for controlling the flow of a fluid from one space or area to another by exploiting the Bernoulli principle, to control the flow of fluid, such as oil and/or gas including any water, from an oil or gas reservoir and into a production pipe of a well in the oil and/or gas reservoir, from an inlet port on an inlet side to an outlet port on an outlet side of the device. The valve includes a movable valve body arranged to be acted on by a temperature responsive device. The valve body is arranged to be actuated towards its closed position by the temperature responsive device in response to a predetermined increase in temperature in the fluid surrounding and/or entering the valve. The temperature responsive device includes an expandable device including a sealed structure at least partially filled with an expandable material.