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If the world is falling apart around you, stopping at the gas station to fill up won’t be an option. Thankfully, the chances are high that you’ll be surrounded by abandoned vehicles, their owners dead or long since gone, and many of them will have full or nearly-full tanks of fuel. The trick is learning how to siphon the fuel out of these tanks and into your own. Here are a few tips to help you siphon gas or other automotive fluids in an emergency.
Understanding the Physics of Siphoning
Before you start collecting pipes and pumps, it’s helpful to understand how siphoning works, and the physics behind it. Liquids are unique in that they have more than one type of potential energy. It will flow with gravity, of course, but it can also flow dependant on its pressure. When you’re siphoning anything — gas, oil, water, etc — you’re using both forms of potential energy — first pressure, to move the liquid into the pipe, and then gravity to encourage it to flow downward. Once you find the equilibrium between these two types of potential energy, the material will continue to flow until its source is exhausted.
Collect Your Tools
At its core, all you really need is a clear length of tubing to siphon gas in an emergency, but this isn’t the best method. Ideally, you’ll want a siphoning kit that includes some sort of pump. There are a number of different siphoning kits available on the market depending on your needs.
If you’re draining oil or other similar fluids, a drain tank might make the job easier. You can siphon oil out of the dipstick tube in a pinch, but it’s a lot easier just to climb under the car and remove the drainplug. The drain tank just gives you the tools to catch and reuse whatever you find.
Choosing a siphoning kit over a length of rubber tubing can also make it easier for you to obtain some fuel, which brings us to our next point.
Choose the Right Car
Don’t pick the newest car on the road if you’re trying to siphon fuel for the first time. Most new cars are equipped with anti-leak technology on their fuel tanks. This keeps gasoline from leaking out if the vehicle ever gets flipped over, but it also makes it more challenging to siphon fuel out of them.
Some of the siphoning kits we mentioned above can help you bypass this anti-leak technology but in a pinch, if all you have is a length of clear tubing, opt for older cars that are easier to siphon from.
Pick Your Method
You’ve got three options when it comes to siphoning fuel in an emergency — pump, air pressure, or mouth-siphoning.
Pumps use suction to draw fuel directly out of the tank. This isn’t siphoning so much as suctioning but it will still get the job done.
Once you have a hose in the tank, if you can increase the air pressure within the tank, you can use this to force the fuel out through the hose. This is a little bit trickier to accomplish but some siphoning kits are designed to do just that.
Finally, there is the mouth siphoning method, which is what you usually see in the movies, where you draw on the siphon hose with your mouth until the fuel starts to flow. Then you put the hose in your receptacle and let it flow until you have enough gas or the tank is emptied. This can work in a pinch if you don’t have any other options, but we don’t recommend it.
Don’t Swallow or Inhale Fuel
This is why we don’t recommend that last method of siphoning fuel unless you’ve got no other option — gasoline is poisonous. You’re supposed to call Poison Control if you inhale or swallow gasoline and may require medical attention or a trip to the hospital. In a survival situation, this isn’t always possible so you might end up killing yourself trying to fill up your car.
If you’re practicing this skill before you actually need it, make sure you’ve got your phone nearby or someone ready to call 911 if you accidentally swallow or inhale fuel.
Closing Thoughts — Don’t Be a Jerk
While being able to siphon fuel can be a great survival skill, don’t use it to be a jerk or steal gasoline from your neighbor’s cars. Save this skill for when you really need it — or when you’ve got a full tank of gas but your lawnmower has run out of fuel and you don’t feel like driving to the gas station again.