How To Drain Gasoline From Car

Ever found yourself in a situation where you need to remove gasoline from your car's fuel tank? Whether you accidentally put diesel in your gasoline engine, have old or contaminated fuel, or need to perform a fuel system repair, draining the gas tank is sometimes a necessary task. This article will guide you through the process safely and effectively.

Why You Might Need to Drain Your Car's Fuel Tank

Draining gasoline from your car isn't something most people do regularly, but it becomes crucial in a few specific scenarios. The most common reason is fuel contamination. Putting the wrong type of fuel in your car – like diesel in a gasoline engine or gasoline in a diesel engine – can cause serious engine damage. Additionally, old gasoline can degrade over time, leading to starting problems and poor engine performance. Draining the tank allows you to remove the contaminated or degraded fuel and replace it with fresh, clean gasoline.

Another reason is for repairs. Certain fuel system repairs, such as replacing the fuel pump, fuel tank, or fuel lines, require a completely empty tank to ensure safety and prevent fuel spillage. Attempting these repairs with a full or partially full tank poses a significant fire hazard and can make the repair process much more difficult.

Finally, you might need to drain fuel for long-term storage. If you plan to store your car for an extended period (several months or longer), draining the fuel tank can help prevent fuel degradation and the formation of gum and varnish deposits in the fuel system. These deposits can clog fuel injectors and lines, leading to starting problems and poor engine performance when you eventually try to restart the car.

Symptoms Indicating a Need to Drain Fuel

Recognizing the symptoms that suggest a need to drain your fuel tank is essential. Here are some common signs:

• Engine misfires or runs roughly: This can occur if the fuel is contaminated or has degraded, affecting its ability to burn properly.
• Difficulty starting the engine: Old or contaminated fuel can make it difficult for the engine to start, especially after the car has been sitting for a while.
• Poor fuel economy: Degraded fuel doesn't burn as efficiently, leading to a decrease in fuel economy.
• Unusual engine noise: A knocking or pinging sound might indicate that the fuel is not burning correctly.
• Check Engine Light illumination: Problems with the fuel system can trigger the Check Engine Light. Diagnostic codes related to fuel mixture or fuel pressure might be present.
• Smell of stale or unusual fuel: Old fuel often has a distinct, unpleasant odor.
• Known misfueling: If you know you put the wrong type of fuel in your tank, draining it immediately is crucial.

Root Causes of Fuel Contamination and Degradation

Understanding the underlying causes of fuel problems is important for prevention and proper diagnosis.

Misfueling: Accidentally pumping diesel into a gasoline car is a common mistake, especially with similar-sized fuel nozzles. The reverse is less common due to diesel nozzles being larger.

Water Contamination: Water can enter the fuel tank through condensation, a loose fuel cap, or contaminated fuel sources. Water can cause corrosion in the fuel system and hinder proper combustion.

Ethanol Absorption: Modern gasoline often contains ethanol, which can absorb water from the air. This water absorption can lead to fuel separation, particularly in older vehicles not designed for ethanol-blended fuels.

Fuel Degradation: Gasoline naturally degrades over time, especially when exposed to air and heat. This degradation leads to the formation of gum, varnish, and other deposits that can clog fuel lines and injectors. The rate of degradation is accelerated in warm climates and with extended storage periods.

Tank Rust & Corrosion: In older vehicles, the fuel tank itself can rust and corrode internally, contaminating the fuel with rust particles and other debris.

Consequences of Ignoring Fuel Problems

Ignoring the symptoms of fuel contamination or degradation can lead to significant engine damage and costly repairs. Here's what can happen if you delay addressing the issue:

• Fuel injector clogging: Deposits from degraded fuel can clog fuel injectors, leading to poor engine performance, misfires, and reduced fuel economy. Replacing or cleaning fuel injectors can be expensive.
• Fuel pump failure: Contaminants can damage the fuel pump, potentially causing it to fail. Replacing a fuel pump is a significant repair.
• Engine damage: Running an engine on the wrong type of fuel or with severely contaminated fuel can cause serious damage to pistons, valves, and other engine components. This can result in extensive and costly repairs. Diesel in a gasoline engine can cause detonation and severe engine damage.
• Catalytic converter damage: The catalytic converter can be damaged by improper combustion caused by contaminated fuel. Replacing a catalytic converter is a costly repair.
• Increased emissions: Poor fuel quality can lead to increased emissions, potentially causing your vehicle to fail an emissions test.

Recommended Fixes: Draining the Fuel Tank

There are a few methods for draining the fuel tank, ranging from DIY to professional service. *Safety is paramount when working with gasoline*. Always work in a well-ventilated area, avoid open flames or sparks, and wear appropriate safety gear, including eye protection and gloves.

Method 1: Siphoning

This is the simplest method but may not be possible on all vehicles due to anti-siphon devices in the filler neck.

1. Gather your supplies: You'll need a siphon hose (specifically designed for gasoline), a large container to collect the fuel, and safety gear (gloves, eye protection).
2. Access the fuel tank: Open the fuel filler door and remove the fuel cap.
3. Insert the siphon hose: Carefully insert the siphon hose into the fuel tank. You may need to maneuver it past any anti-siphon devices. Never suck on the hose to start the siphon! Use a siphon pump or a self-priming siphon hose.
4. Start the siphon: Once the hose is properly positioned, start the siphon by using the pump or other method provided with your siphon hose.
5. Collect the fuel: Ensure the receiving container is lower than the fuel tank. Monitor the flow and stop the siphon when the tank is empty or at the desired level.
6. Dispose of the fuel properly: Take the used gasoline to a hazardous waste disposal facility or recycling center. Do not pour it down the drain or into the ground.

Warning: Some vehicles have anti-siphon devices that prevent this method. Forcing the hose can damage the fuel system. If you encounter resistance, try another method.

Method 2: Disconnecting the Fuel Line

This method offers more complete drainage but requires more mechanical skill.

1. Gather your supplies: You'll need wrenches, pliers, a fuel line disconnect tool (if required), a large container, safety gear, and rags.
2. Locate the fuel line: Identify the fuel line that runs from the fuel tank to the fuel filter or engine. This line is usually located underneath the car, near the fuel tank. Consult your vehicle's service manual for the exact location.
3. Relieve fuel pressure: Before disconnecting any fuel lines, relieve the fuel pressure in the system. This can often be done by removing the fuel pump relay or fuse and starting the engine (it will run for a short time and then stall). Consult your vehicle's service manual for specific instructions.
4. Disconnect the fuel line: Carefully disconnect the fuel line at a convenient point. Some fuel lines use quick-disconnect fittings that require a special tool. Have a container ready to catch the fuel as it flows out.
5. Drain the tank: Allow the fuel to drain completely into the container. You may need to raise the rear of the car to facilitate complete drainage.
6. Reconnect the fuel line: Once the tank is empty, reconnect the fuel line securely.
7. Dispose of the fuel properly: Take the used gasoline to a hazardous waste disposal facility or recycling center.

Warning: This method involves working with fuel lines under pressure. Relieving the pressure is critical to prevent fuel spraying and potential fire hazards. Be extremely cautious and follow all safety precautions.

Method 3: Using the Fuel Pump (Professional Method)

This is the preferred method for many professional mechanics. It involves disconnecting the fuel line and using the car's own fuel pump to drain the tank. This method is generally safer and more efficient than siphoning.

1. Gather supplies: Wrenches, pliers, fuel line disconnect tool, a large container, safety gear, rags, and wire to jump the fuel pump relay.
2. Locate the fuel line and fuel pump relay: Identify the fuel line that runs from the fuel tank to the fuel filter or engine. Locate the fuel pump relay in the fuse box (consult your owner's manual).
3. Disconnect the fuel line: Carefully disconnect the fuel line at a convenient point. Attach a hose to the fuel line and run it to your container.
4. Jump the fuel pump relay: Remove the fuel pump relay and use a jumper wire to connect the appropriate terminals in the relay socket. This will activate the fuel pump. Consult your vehicle's wiring diagram to identify the correct terminals.
5. Drain the tank: The fuel pump will now pump the fuel out of the tank and into the container. Monitor the flow and stop the pump when the tank is empty or at the desired level by removing the jumper wire.
6. Reconnect the fuel line and relay: Once the tank is empty, reconnect the fuel line securely and replace the fuel pump relay.
7. Dispose of the fuel properly: Take the used gasoline to a hazardous waste disposal facility or recycling center.

Warning: This method requires knowledge of automotive electrical systems and the ability to correctly identify and jump the fuel pump relay. Incorrectly jumping the relay can damage the electrical system. *If you are not comfortable with this procedure, consult a qualified mechanic.*

Cost Estimates and Shop Advice

If you're not comfortable draining the fuel tank yourself, it's best to take your car to a qualified mechanic. The cost of this service can vary depending on the complexity of the job and the shop's labor rate. Generally, you can expect to pay between $100 and $300 for a professional fuel tank draining service. This price typically includes draining the fuel, inspecting the fuel system, and properly disposing of the old fuel.

When choosing a mechanic, look for a shop with experience in fuel system repairs and a good reputation. Ask for a written estimate before authorizing any work and make sure you understand what's included in the price.

While there are no specific Technical Service Bulletins (TSBs) universally addressing fuel tank draining procedures, manufacturers often release TSBs related to fuel system problems caused by contaminated or degraded fuel. These TSBs may provide specific diagnostic and repair procedures for your vehicle. Your mechanic can access these TSBs through professional databases.

Remember, working with gasoline can be dangerous. If you're unsure about any step in the process, it's always best to consult a professional mechanic. Prioritizing safety is paramount when dealing with flammable materials.