How to Siphon Gas in an Emergency

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Estimated reading time: 9 minutes

We live in a highly mobile society, with our lifestyles and our cities built around the idea that people can drive around in cars. While some people use mass-transit to get around, that only accounts for five percent of US workers. Even then, some of those people use mass-transit to get to work, but have a car at home for running errands and other needs.

The automobile clearly transformed society; but it is not without its failings. Cars break down and they need a constant supply of gasoline to burn. Without that gasoline, all those cars, trucks and SUVs on the roads are just piles of machined parts, connected together.

Yet there are many emergency scenarios where gasoline may not be readily available. Any loss of the power grid would make it impossible to pump gas at the station. As I sit here writing this, much of New Orleans is without power, due to Hurricane Ida. As happened after Hurricane Katrina, chances are pretty high that many of those people will be without power for weeks.

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Another situation where gasoline is going to be a very real problem is in the case of a mass bug out. There is no city in the country with sufficient highway capacity to handle a mass evacuation. The pictures we’ve all seen of miles upon miles of cars, stalled in traffic, would be very real in a real evacuation. Some of those cars would overheat and many would run out of gas. With the difficulty in getting gas to those drivers, some will abandon their cars and head out on foot.

The one source of gasoline that pretty much always exists is the gas that is in the tanks of other cars; specifically cars that are parked rather than stalled on the road. The possibility exists of siphoning gas out of those cars to burn in our own.

Let’s Talk Ethics for a Moment

Before talking about how to siphon gas, let’s talk about whether or not we should. The dictionary defines looting as “stealing goods (from a place), typically during times of war or riot.” While the dictionary doesn’t specifically include disasters in its definition of looting, it is commonly understood and used that way as well. Scavenging, on the other hand, is defined as “searching for and collecting anything usable from discarded waste.”

Those two definitions don’t exactly line up with each other, but I think we can extrapolate our own definition from them. The situations talked about for looting really are immaterial, as we wouldn’t be trying to siphon gas if the situation wasn’t pretty bad.

What we’re really talking about is whether we would be stealing or collecting discarded waste. Based on that, siphoning gasoline from the car parked next to you would be stealing, while siphoning it from a car that went off the road and was abandoned by the owner would be scavenging. Likewise, siphoning gas from a car parked at a neighbor’s home, when that neighbor had bugged out could be fairly called scavenging.

Let’s Talk Methods

There are several ways that gasoline can be scavenged from vehicles. One thing they all have in common is that we need to gain access to the gas tank. Auto manufacturers made this harder for us back around the first oil crisis in 1973. With the scarcity of gasoline and rising prices, stealing gas was becoming commonplace. In response to this, auto manufacturers started putting the fuel filler behind a small door that was opened with a key or by pulling a lever inside the car.

This is a fairly decent security measure, if you’re trying to protect that gasoline from casual theft. Like securing a home from burglars, the idea isn’t so much making it hard to steal, as it is making it hard to steal without it being noticeable. But it’s not all that hard to get that door open; all it takes is a small crowbar.

Once the door is opened, the next barrier is a small spring-loaded door which is there to prevent the nozzles for “regular” gasoline from being inserted into the fuel filler. This is easily pushed aside, either with the siphon hose or a screwdriver.

Siphoning functions by gravity, so it is basically impossible to siphon gas directly from one vehicle’ s tank to another. Rather, the gas is siphoned out of the donor vehicle into a container, such as a gas can. It can then be poured into your vehicle. For it to siphon, the container must be lower than the level of the fuel in the gas tank. The greater the distance below the tank, the faster the gas will flow.

With a Pump

The safest and easiest way to siphon gas is with a pump. Of course, that means buying a siphon pump before it is needed, as it probably won’t be available when it is. These pumps come in both manual and electric versions, which plug into the vehicle’s accessory connector. The manual ones usually have a plastic bulb that you squeeze to create a vacuum, drawing the gas out of the tank; but there are also hand crank versions, which are more costly but easier to use.

To siphon the gas, the hose at one end of the pump is inserted through the flapper in the fuel filler of the donor car and the hose at the other end is inserted into the container. The end in the tank must be inserted far enough to get to the bottom of the vehicle’s gas tank. To make sure that happens, estimate the distance and hold the hose there with one hand; keep feeding it into the tank until that hand reaches the fuel filler.

It is important that the right hose be inserted into each end, as the pump doesn’t work in reverse. Then just turn on the pump to start the gas flowing. Once gas is flowing, you can stop pumping with the manual pumps, as the gas will flow on its own. Stop the flow by either pinching the hose shut, raising it up above the level of the gas tank or removing it.

With a Hose

The “classic” way of siphoning gasoline from a car’s gas tank is with a piece of hose. It is best to use clear hose for this, so that the gasoline can be seen through it, when it starts to flow. Getting gas into your mouth tastes bad and isn’t all that good for your health.

Stick one end of the hose into the donor vehicle’s fuel filler. As with a pump, it is important to ensure that it goes far enough in so that it reaches the bottom of the tank. Then exhale completely and take the other end of the hose into your mouth. Start sucking the air out of the hose, watching for the gasoline all the time. When the gas is just about to your mouth, pull the hose out rapidly, lowing it to encourage the gas flow. Place it in the container to siphon out the gas, which can then be transferred to your vehicle.

From The Fuel Lines

This one’s a bit harder to do, especially now that most vehicles have the fuel filter inside the gas tank and the fuel lines are usually made of steel. But even then, there is usually a short section of rubber hose at the engine end of that fuel line. The idea here is to use the vehicle’s fuel pump to pull the fuel out of the tank. This requires attaching battery power directly to the pump.

However, that pump is not readily accessible without removing the tank, something that really shouldn’t be tried with the tank full. So we do what mechanics do to siphon the fuel out of the tank. That’s to find the wires leading to the fuel pump (they’ll be the only wires under the car that go over the tank) and cut them, attaching two wires from there to either the vehicle’s battery or another 12 volt battery.

It’s hard to say what colors the wires will be, if they are red and black, the red is the positive; but if they are another color combination, you’ll need to experiment with how to hook them up. When the pump is running, you’ll be able to hear it, so if you don’t hear it, then you’ve got the wires switched.

Don’t do that until you’re ready to catch the fuel coming out the other end. That means locating the fuel lines (there are two of them). Underneath the car, these will run along the inside of the passenger side frame rail. There may be a filter, looking like a small can, somewhere in the pressure line. If there is, you can disconnect that filter and collect the gasoline there.

More modern cars won’t have a fuel filter under the car, so the gas will need to be collected where the fuel lines connect to the engine. These will come up the back of the engine compartment from the vehicle’s underbody, probably on the passenger side.

If you’re not a mechanic, it can be hard to tell which one is the pressure line and which one is the return. The pressure line goes to a regulator, which is attached to the fuel rail that supplies fuel to the injectors. The return line is attached to the other end of the fuel rail and doesn’t have that regulator. If you’re not sure which is which, plan on using both.

That means extending the fuel lines by cutting them and attaching longer hoses to them, which are then placed in your collection container. Once you start the pump, the fuel will start flowing immediately; but it will only flow for a few seconds if the lines are still connected to the engine, as a pressure sensor in the pump will shut off the pump. But if the lines are cut, the fuel will continue to flow until the tank is empty or the battery is disconnected.

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