How To Siphon Gas

Last Updated: September 14, 2022

There are many legitimate reasons to learn how to siphon gas, even though this technique is typically linked with criminal activity. If you become stranded a long way from a gas station, understanding how to siphon gas can help you get back on the road.

You can empty the gas tank to prepare lawnmowers, snowblowers, and other gas-powered equipment for the winter or summer. In an emergency, you can even siphon gas from your car into the gas tank of your lawn mower or the other way around.

Step-By-Step Guidelines

Unlock The Fuel Door

This is the simplest section. It’s simple enough to use force to unlock the fuel door, even if you have no experience picking locks. A crowbar or the hammer’s claw on the back can be used.

Push The Flap Covering The Filler Pipe Aside Using A Screwdriver

The majority of fuel pipelines have a small metal flap covering them. However, the flap will become stuck if you remove the siphon pipe. All you need is something long and slender, like a screwdriver, to go around this. To hold the flap open, move the flap aside with the screwdriver.

Siphon The Gas

Incorporate the siphon hose’s tank end into the tank and a fuel canister with the other end. Siphons are one-way devices, so bear that when inserting the hose into the tank. The gas will be drawn into your canister from the tank by pressing the valve.

*Avoid siphoning gas with the mouth as was once the norm! It’s simply too dangerous to risk swallowing gasoline. A squeeze-bulb siphon will render the task much simpler.

However, the vehicle features an anti-siphon valve!

The likelihood that an automobile has an anti-siphon mechanism increases if you’re trying to steal gas from one that isn’t very old. You must get around this if you wish to drain the petrol tank.

What is an Anti-Siphon Valve?

You can use one of two devices to stop someone from siphoning gas from a vehicle. An anti-siphon screen comes first. Because of the mesh screen, you can’t put anything substantial into the gas tank. This is normally found higher up in the gasoline filler pipe.

A “rollover valve” at the tank intake serves as the second device. Since it stops you from inserting a siphon hose into the tank, this valve is sometimes known as an anti-siphon valve. Its purpose is to prevent gas from fleeing the vehicle in the event of a rollover.

How To Bypass An Anti-Siphon Valve

Method 1: Slope Parking

With this easy approach, you can probably siphon most of the gas from a car with an anti-siphon screen but no rollover valve. The anti-siphon screen is typically positioned relatively far down the neck of the fuel filler pipe, which is why it functions.

Simply place the automobile on an incline so that the filler is downward. You can siphon part of the gasoline out by reaching it with your siphon hose.

Method 2: Remove The Anti-Siphon Screen.

It is possible to get past a car’s anti-siphon screen. This is not something I advise since if any piece of the screen falls into the tank, you can end up blocking the fuel outflow.

To pierce the anti-siphon screen, you’ll need a long, pointy object to pierce the anti-siphon screen. Metal touching metal can ignite, which is an issue. And a single spark may start a huge conflagration!

Copper can be a suitable alternative. Copper typically does not spark because of its strong conductivity. Copper wire likely won’t have enough strength to pierce the screen. A copper ring that is soldered to a copper pipe is one remedy. The screen is then broken using the ring at the pipe’s end after you’ve fed it into the gasoline filler tank.

If the vehicle merely has an anti-siphon screen, you can siphon fuel after shattering the screen. You must, however, bypass the rollover valve if it is present (see method 3).

Method 3: Override The Rollover Valve

Gas can only flow in one way into the tank thanks to car rollover valves. Typically, rollover valves are either butterfly or ball-type valves.
The rollover valve may, in theory, be bypassed with the appropriate equipment. However, doing this requires a great deal of both time and effort. This procedure should be skipped if the vehicle has a rollover valve and uses methods #4 or #5.

Getting around the rollover valve:

• You will require roughly 8 feet of plastic hose 1/4 inch in diameter. It needs to be rigid but still flexible.

• To make the hose end narrow, cut it at an angle.

• Insert the hose into the gas tank.

• When you press the rollover valve, twist and push the lever. This should allow the hose to enter the fuel tank and pass the valve.

• Connect the 14-inch hose’s end to a thicker hose.

• Attach the heavier hose to the bulb siphon pump.

• Because the line is so small, siphoning a gallon of petrol will require an active squeeze for roughly five minutes.

Once more, this approach is much trickier than it seems, especially since there’s no way to tell if the hose is certainly getting through the valve.

If you’re interested in giving it a shot, I suggest purchasing a spare rollover valve and giving it a go. Observing what you’re doing will help you determine the proper motions to insert the hose into the valve.

Method 4: Drain The Fuel By Disconnecting The Gasoline Line

You can access the fuel from the tank’s opposite side without attempting to breach the anti-siphon screen or/and valve. For this:

• Find the gasoline line.

• Cut off the fuel line. For this, you might require a specialized tool (like this). You can create your gasoline disconnect gadget.

• Join a hose to the gasoline line’s terminus. Incorporate your canister with the hose’s other end.

• Start the automobile. Gas will leak from the tank and enter the canister thanks to the fuel pump. To maintain the gas flowing, you must continuously turn the automobile on and off.

• You can jump the fuel pump relay connections if unable to start the vehicle. You can do this while turning off the engine if you have a jumper.

Method 5: Employ A Bypass Valve And A Fuel Pressure Tester

The anti-siphon valve can be bypassed by using the fuel tank Schrader valve. Pressure tests are performed using the gasoline Schrader valve. However, since not many automobiles have a line of fuel of Schrader valves, this sometimes may not be an option.

If a Schrader valve is present, you must purchase a fuel pressure kit test using a bypass valve (such as this one). The bypass valve line should be connected and placed in a canister, and the vehicle should be started before turning the bypass on. In the canister, the fuel will flow.

This method only functions if you can start the car. This leaves you with just the option of stealing fuel from your vehicle unless you also know how to kickstart a current car.

Method 6: Make A Hole In The Gas Tank

The last resort for getting gas out of a vehicle is to drill a hole in the tank. Gas will enter the hole if a canister is placed beneath it.

In addition to the gasoline tank being destroyed, drilling into metal fuel tanks poses a significant fire danger. Metal contacting metal will produce sparks, which may cause the gas in the tank to ignite. Do this only on automobiles using plastic (polymeric) gas tanks.

Some of these techniques for siphoning gas require starting the vehicle’s engine. The risk of handling fuel while the engine is operating is constant. For your safety, you should:

• Employ a longer hose. Most siphon kits have a hose just 2 to 3 feet long. Use a longer hose to place the fuel canister farther from the vehicle.

• Only siphon several gallons at once. From the tank, release a few gallons. Once the vehicle has stopped, move your canister from the way. You shall not have excess fuel nearby the car at once if you do it in this manner.

• Draw water from a cool engine. Before disconnecting anything, let the engine finish cooling down entirely.


Knowing how to siphon gas is essential to dispose of stale fuel if you run out of fuel and yourself stranded or need to borrow fuel for an empty mower or snow machine tank.

Remember that it is against the law to siphon gas from a vehicle that is not your own without the owner’s consent. In addition, there are unsafe ways to steal gas without utilizing a pump that should never be tried.

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