Warning!Ingesting gasoline can cause harmful effects like blindness, lung damage, coma, and may even lead to death.Certain situations may call for siphoning gas from a vehicle. Whether you decide to use a lawnmower, a generator, or simply replace the fuel pump of your car, the first step is to extract fuel from it. Gas tanks filled with ethanol gas frequently need siphoning, as such fuel is known to quickly go bad.Siphoning gas from a car involves simple principles of physics. In most cases, air is sucked out of a pipe dipped in the tank, creating a vacuum. The gas then flows into the pipe to fill up the vacuum. It falls into the container from the pipe under the action of gravity. As fuel in the tank becomes lesser, it creates a new vacuum, which is filled up by air rushing inside from the tank opening. This air exerts pressure on the gasoline, making it continuously flow into the pipe, until the pipe is raised high enough to make gravity act in the reverse direction.
Siphoning gas from most modern cars is easier said than done. But, since it’s not impossible, there’s no need to lose heart. The various methods to siphon gas from both, older and modern cars, is given here.
Things Needed
- Fuel-approved container
- Transparent plastic hose or pipe
- Cloth
- Vacuum pump
- Screwdriver/chopstick
Older CarsManual Suction
► Place the container in which you want to store fuel below the gas tank, after opening it.
► Open the gas tank and insert a long plastic tube inside. To check if it is submerged, blow air into it, and you should hear bubbling noises.
► Create a loop in the pipe, such that the other end is facing upwards. This mechanism helps control the gas flow better while sucking.
► Take the end of the pipe facing you and begin sucking carefully. The transparency of the pipe will allow you to see the gas flowing through it.
► Keep sucking until the gas reaches the bottom of the loop, which should be a foot away from your mouth. Remove it from your mouth and plug it shut with a finger.
► Carefully lower this end into the open container, without pulling the other end of the pipe from within the tank. Once inside the container, remove the finger from the pipe, which will cause the gas to flow into it.
► When you have removed enough gas, or if the container is about to get full, again clamp the end of the pipe shut. Raise this end higher than the level of the tank and unplug it to drain off the remaining gas back into the tank. Fix the lid back on the tank.With Two Pipes
► Get two transparent plastic pipes, such that one is much longer than the other.
► Insert the longer pipe deep into the tank, and put its other end into an open container placed at a lower level than the tank.
► Take the shorter pipe and insert one of its ends deep within the tank, such that both pipes have one end inside the tank.
► Now, seal the tank opening by plugging a large wet cloth in it. The aim is to make the opening air-tight, despite the pipes going inside.
► Take the open end of the short hose in your mouth and blow air into it. This is relatively safer than sucking gas out of the tank, but for more safety, connect it to a vacuum pump.
► Blowing air inside the tank raises the pressure in it since the opening is sealed. This pressure acts on the gas surface, and forces it out through the other pipe.
► To stop the gas flow, plug a finger on the end of the long pipe, and raise it higher than the gas tank. Carefully release the finger to drain the remaining fuel back into the tank.With Mechanical Pump
► A vacuum pump works the same way as manually sucking the gas out, but protects the user from ingesting gasoline or its fumes. It’s the best and most reliable way to siphon gas.
► First, identify the input and output ends of the pump. This is vital, as inserting the wrong end will blow air into the tank, rather than drawing gas out of it.
► Place an open container below the gas tank. Then, remove the tank lid.
► Insert the input end of the pipe inside the tank until it gets submerged or reaches the bottom. Then, place the output end of the pipe inside the container.
► Depending on the type of vacuum pump, you may have to press a bulb or turn a squeeze-valve to begin transferring the gas. Some pumps require repeated pressing, while others are automatic.
► When the container is full, close the valve or raise the output end higher than the gas tank, after clamping it shut with a finger. Drain off the gas remaining in the pipe back into the tank.Modern Cars
► All modern cars come with a siphon-proof filter in the gas tank. This consists of a metal flap which clamps shut and prevents any hose from entering the tank.
► To siphon gas from such a tank, you can either use the manual suction method or the siphon pump method. But for it to work, the metal flap has to be held open using a long object like a screwdriver or a chopstick.
► Using metallic objects like a screwdriver is not recommended, as it can create a spark which can be deadly. In case you are using one, make sure it is grounded with the car body.
► The best option is to wedge a chopstick into the tank opening to hold the flap open. Now, this allows siphoning of gas with a hose. If required, a friend can hold the chopstick in place.
► Some cars come with a ball-shaped anti-siphon valve, which, while allowing gas-filling, does not allow the entry of pipes. The above methods do not work on such cars.
► Many products like the GasTapper are available in the market, which can be used to siphon fuel from cars with ball-shaped valves. They have a thin inlet pipe which passes into the tank through the space around the ball valve, and is connected to a suction pump.Now that you know how to siphon gas from a car tank, it’s best to understand the dangers involved. Gas is highly inflammable, and the vapors from the open tank even more so. While it is also possible to extract gas by drilling into the tank from below, it’s easy to generate sparks by this method, which is best avoided.