# How do you siphon Gas from New Cars

**URL:** <https://boards.straightdope.com/t/how-do-you-siphon-gas-from-new-cars/197438>\
**Category:** Factual Questions\
**Created:** [August 25, 2003, 2:25am UTC](https://boards.straightdope.com/t/how-do-you-siphon-gas-from-new-cars/197438 "2003-08-25T02:25:59Z")\
**Posts on this page:** 6\
**Page:** 1

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**Author:** ![blasphmer](https://avatars.discourse-cdn.com/v4/letter/b/6de8d8/32.png) [@blasphmer](https://boards.straightdope.com/u/blasphmer)\
**Post date:** [August 25, 2003, 2:25am UTC](https://boards.straightdope.com/t/how-do-you-siphon-gas-from-new-cars/197438/1 "2003-08-25T02:25:59Z")

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Ok, serious mechanical not thug question here. With the recent power failures and not having a well stocked house; how would I have defeated the anti-siphon mechanism on my car? Even pulling the fuel line only gives 6 oz. of fluid before shutting down for the crash pump shutoffs. (American cars we’re talking here)

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**Author:** ![Reeder](https://avatars.discourse-cdn.com/v4/letter/r/c6cbf5/32.png) [@Reeder](https://boards.straightdope.com/u/Reeder)\
**Post date:** [August 25, 2003, 2:51am UTC](https://boards.straightdope.com/t/how-do-you-siphon-gas-from-new-cars/197438/2 "2003-08-25T02:51:46Z")

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Just curious…in a power failure…what do you need gasoline for?

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**Author:** ![Rick](https://avatars.discourse-cdn.com/v4/letter/r/9f8e36/32.png) [@Rick](https://boards.straightdope.com/u/Rick)\
**Post date:** [August 25, 2003, 3:00am UTC](https://boards.straightdope.com/t/how-do-you-siphon-gas-from-new-cars/197438/3 "2003-08-25T03:00:29Z")

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> [@](#):
>
> \*Originally posted by blasphmer \*  
> \*\*Ok, serious mechanical not thug question here. With the recent power failures and not having a well stocked house; how would I have defeated the anti-siphon mechanism on my car? Even pulling the fuel line only gives 6 oz. of fluid before shutting down for the crash pump shutoffs. (American cars we’re talking here) \*\*

First off what anti-syphon mechanism? Are you refering to the little flapper door in the filler neck? The answer is just push a hose past it.

Electric fuel pumps don’t run unless the engine is running for safety reasons. Most systems do build pressure for easy startup by running the pump for about 1 second when the key is turned on.

You can jumper the fuel pump relay (On cars that have one) and the pump will run full time.

**Siphoning gas by mouth is flat out dangerous and should NEVER be attempted. Furthermore getting gas out of a auto using the fuel pump can also be very dangerous. I know of one case where an individual burned a new car to the ground attempting this. In the long run a gas can and a trip to the station is much easier.**

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**Author:** ![Q.E.D](https://avatars.discourse-cdn.com/v4/letter/q/51bf81/32.png) [@Q.E.D](https://boards.straightdope.com/u/Q.E.D)\
**Post date:** [August 25, 2003, 3:00am UTC](https://boards.straightdope.com/t/how-do-you-siphon-gas-from-new-cars/197438/4 "2003-08-25T03:00:54Z")

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> [@](#):
>
> \*Originally posted by Reeder \*  
> \*\*Just curious…in a power failure…what do you need gasoline for? \*\*

Well, generators don’t run on water, you know.

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**Author:** ![Q.E.D](https://avatars.discourse-cdn.com/v4/letter/q/51bf81/32.png) [@Q.E.D](https://boards.straightdope.com/u/Q.E.D)\
**Post date:** [August 25, 2003, 3:06am UTC](https://boards.straightdope.com/t/how-do-you-siphon-gas-from-new-cars/197438/5 "2003-08-25T03:06:54Z")

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> [@](#):
>
> \*Originally posted by Rick \*  
> **First off what anti-syphon mechanism? Are you refering to the little flapper door in the filler neck? The answer is just push a hose past it.**

I believe farther in the filler neck is a spiral cone-shaped springy thing that lets gas flow past, but prevents a siphon hose from beign fed into the tank itself.

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**Author:** ![John\_Kentzel-Griffin](https://avatars.discourse-cdn.com/v4/letter/j/ccd318/32.png) [@John\_Kentzel-Griffin](https://boards.straightdope.com/u/John_Kentzel-Griffin)\
**Post date:** [August 25, 2003, 3:10am UTC](https://boards.straightdope.com/t/how-do-you-siphon-gas-from-new-cars/197438/6 "2003-08-25T03:10:25Z")

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We’re not going to assist in defeating anti-theft devices.

This is closed.

**DrMatrix** - GQ Moderator