Air in the fuel tank: Causes, symptoms, and solutions

Air in the fuel tank is one of the problems that many drivers may encounter. This issue not only disrupts engine performance but can also damage various components of the fuel delivery system. In this article from the series of general car repair articles, we will thoroughly examine the causes and symptoms of air in the fuel tank, as well as the solutions to this problem.

What are the causes of air in the car's fuel tank?

The presence of air in the fuel tank can have various reasons, the most important of which are:

Cracks in the fuel tank: Even the smallest crack in the fuel tank can allow air to enter the tank. These cracks may occur due to impact, corrosion, or wear.

Clogged fuel transfer line: Deposits and contaminants that accumulate over time in the fuel transfer line can cause blockages and create a vacuum in the system. This vacuum allows air to enter the system instead of fuel.

Problem with the fuel tank vent: The vent is responsible for preventing air from entering the tank and directing fuel vapors outside. Clogging or malfunctioning of the vent allows air to easily enter the tank.

Leaks in the fuel transfer pipes: Any leaks in the fuel transfer pipes can allow air to enter the system.

Fuel pump failure: The fuel pump is responsible for pumping fuel to the engine at the right pressure. A malfunctioning fuel pump can reduce fuel pressure and create a vacuum in the system.

Injector failure: The injector is responsible for spraying fuel into the engine cylinder. Injector failure can cause fuel leaks and create a vacuum in the system.

Factors that exacerbate air in the fuel tank:

Low-quality fuel: Using low-quality fuel increases the formation of deposits in the fuel delivery system and consequently increases the likelihood of clogging the fuel transfer line.

Failure to timely replace the fuel filter: The fuel filter is responsible for filtering the fuel. Failure to replace the filter on time leads to the accumulation of contaminants and blockage of the fuel line.

Impact on the fuel tank: Hitting the fuel tank can cause cracks or loosen connections.

Symptoms of air in the car's fuel tank

The main symptoms of air in the fuel tank include:

Fuel backing up during refueling: This is one of the most obvious signs. When you fill the tank, fuel backs up from the tank opening.

Car not starting or failing to start: The presence of air in the fuel delivery system can disrupt engine performance and even prevent the car from starting.

Car stuttering and shaking while driving: Fluctuations in engine performance due to the presence of air in the fuel.

Increased fuel consumption: The presence of air in the fuel reduces engine efficiency and increases fuel consumption.

Car stalling while driving: Especially on inclines or during sudden accelerations.

Hissing sound from the fuel tank area: This sound is caused by the creation of a vacuum in the fuel delivery system.

Reduced engine power: The presence of air in the fuel reduces engine power and vehicle acceleration.

Smell of fuel around the car: In some cases, a smell of fuel may be detected around the car, indicating a fuel leak or a problem in the fuel delivery system.

Air in the fuel tank

Take the consequences of air in the fuel tank seriously!

The presence of air in the fuel tank can have serious consequences for the vehicle, including:

Disruption of engine performance: The presence of air in the fuel-air mixture prevents complete combustion. As a result, the car's engine may stutter, lose power, and even fail to start.

Increased fuel consumption: Due to incomplete combustion, the engine requires more fuel to produce the same amount of power, resulting in increased fuel consumption.

Reduced lifespan of engine components: Incomplete combustion can lead to carbon deposits in the engine and damage components such as spark plugs, valves, and pistons.

Damage to the fuel pump: The fuel pump is designed to pump fuel. Pumping air puts excessive pressure on the pump and can lead to premature failure.

Damage to the injectors: The presence of air in the fuel can cause clogging of the injectors and reduce the accuracy of fuel spray.

Increased emissions: Incomplete combustion leads to increased emissions of harmful pollutants such as carbon monoxide and hydrocarbons.

Damage to the catalytic converter: The catalytic converter is responsible for reducing vehicle emissions. The presence of more pollutants due to incomplete combustion can damage the catalytic converter.

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How to bleed the fuel tank of a car?

The exact method of bleeding the fuel tank may vary depending on the type of vehicle and the reason for bleeding. However, in general, there are several common methods for bleeding the fuel tank:

Frequent and complete refueling:

Fill the fuel tank as much as possible.

Repeat this several times. With each refueling, some of the air will be expelled from the tank.

Starting the car and idling:

After a full refuel, start the car and let it idle for a few minutes. This helps the fuel pump expel air from the system.

Opening fuel line connections (with the help of a specialist):

This method should be performed by a skilled mechanic. In this method, some connections of the fuel lines are opened to drain the air from the system.

Be sure to read: When is the best time to replace car filters?

Ways to prevent air in the fuel tank

To prevent this problem, you can take the following measures:

Use high-quality fuel: High-quality fuel is less likely to create deposits and reduces the likelihood of clogging the fuel line.

Timely replacement of the fuel filter: Replace the fuel filter according to schedule to prevent clogging.

Periodic inspection of the fuel delivery system: Periodically have the vehicle's fuel delivery system inspected by a qualified mechanic.

Protect the fuel tank: Prevent damage to the fuel tank. Impact on the tank can cause cracks.

Pay attention to the quality of refueling: Use reputable gas stations and avoid refueling from open tanks.

Proper vehicle maintenance: By properly maintaining the vehicle, prevent technical problems that lead to air in the fuel tank.

Pay attention to early signs: If you notice signs such as reduced acceleration, increased fuel consumption, or unusual noises from the engine, quickly visit a mechanic.

Learn more: Repairing and replacing the car's fuel pump and filter, from causes of failure to costs

When should you visit a mechanic?

If the problem of air in the fuel tank persists despite following home remedies, it is better to consult a specialized mechanic. The mechanic can diagnose and resolve the issue using specialized equipment.

Final words

Air in the fuel tank can create serious problems for the vehicle. By familiarizing yourself with the causes, symptoms, and solutions to this problem, you can take timely action and prevent more serious issues from arising.

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