Originally Posted by johnsongrass1
My Toyota has a Ball valve in the fill neck and so does my Subaru.
That is the rollover valve.
Cars have had them for years now.
Many are built into the fill neck at the tank, and not in the tube , as it is harder for anyone to defeat that way.
- It provides a method of controlled escape for gasoline vapors during the refueling process. It has a mechanism which closes the vent in the event the vehicle rolls over, to prevent spilling of VOCs or fuel in general. It also acts as a fill limiter.