Where does the air go?

[MABurns]

In my older trucks changing the fuel filter was somewhat of a pain because of priming the fuel filter and making sure you got all the air out (one time I had dificulty getting it started).



Now it is no big deal to do, but my question is without bleeding air out, where does the air go that is in the filter housing? Pushed out through the injectors?

 

[JVolpe]

I assume the return line, but could be wrong.

 

[WoodChuck]

Back to the fuel tank.