# Why are there 3 vent lines from the gas tank (2005 Subaru Outback)

**URL:** <https://boards.straightdope.com/t/why-are-there-3-vent-lines-from-the-gas-tank-2005-subaru-outback/801568>\
**Category:** Factual Questions\
**Created:** [November 13, 2017, 11:11pm UTC](https://boards.straightdope.com/t/why-are-there-3-vent-lines-from-the-gas-tank-2005-subaru-outback/801568 "2017-11-13T23:11:14Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![kanicbird](https://avatars.discourse-cdn.com/v4/letter/k/5f8ce5/32.png) [@kanicbird](https://boards.straightdope.com/u/kanicbird)\
**Post date:** [November 13, 2017, 11:11pm UTC](https://boards.straightdope.com/t/why-are-there-3-vent-lines-from-the-gas-tank-2005-subaru-outback/801568/1 "2017-11-13T23:11:14Z")

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When I look at a modern car fuel tank venting ‘evac system’ I see one vent line. Yet my ride has 3. A 2005 Subaru Outback. One goes to a valve right by such connection. Another seems to run forward, another runs though the cargo area (under metal shielding). What are each of these 3 for?

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**Author:** ![Khendrask](https://avatars.discourse-cdn.com/v4/letter/k/3e96dc/32.png) [@Khendrask](https://boards.straightdope.com/u/Khendrask)\
**Post date:** [November 14, 2017, 12:28pm UTC](https://boards.straightdope.com/t/why-are-there-3-vent-lines-from-the-gas-tank-2005-subaru-outback/801568/2 "2017-11-14T12:28:32Z")

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Just because I was looking into this recently for a neighbor, I happened to find this reference:

[Suburu fuel tank venting](http://www.subaruoutback.org/forums/66-problems-maintenance/405009-fuel-tank-vent-valve-operation-99-a.html)

That is on an older model, but I don’t imagine they have changed much.  
In my neighbors case, the lever that activates the shut off valve broke, preventing him from filling the tank. Weird.