Ask the Editors: Disappearing Gas Tank Hose
Gas tanks, much like human beings, have to breathe. This is a lesson anyone with a sealed plastic gas can in a hot shed learns fairly early on in the form of a hissing pressure-release once they begin to unscrew the cap. Every single fuel tank made must have a vent somewhere that will relieve pressure and compensate for vacuum.
While we like to think that our fuel remains right where we leave it once we pour it in the tank, the reality is that gasoline is in a constant state of fluctuation: It expands in volume as it warms up and shrinks in volume as it cools down. The fuel level in your tank is constantly changing throughout the day – even when just sitting in place in the garage.
The vent hose is a simple and effective means of allowing for adequate venting but can be cumbersome, prone to snagging on trail foliage and easily lost. Manufacturers are simply transitioning to the costlier hoseless vented cap for these reasons. While it’s tough to tell by looking at them; these caps are in fact vented by using an internal check valve. Without it, your fuel tank would be bowing out and sucking in depending on the temperature at any given time.
