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Air in the Fuel Line: Symptoms & Solutions

Every car engine part is equally important; if a simple function does not work, the whole system can break down. Many times it’s hard to get the source of the problem as a problematic symptom can be the reason for several issues.

However, this article will break down all you should know about the air in fuel lines, why it happens, its symptoms, how to fix it, and more.

Can air be trapped in the fuel line?

Air can be trapped in the car fuel line. When air traps in the car fuel system, most people think the air filter is causing the issue, but most of the time, the fuel inlet line from the tank is responsible for the problem.

A fuel suction system pulls the fuel from the tank and pusses it into the filter and engine.

If that pipe is clogged, the fuel cannot pass freely, but the system does not stop the suction system. If there is some weak point in the pipe connections of the filter, air enters the system continuously.

IF there is a pinhole between the tank’s fuel line and the fuel passing system, air can get into the fuel line. It usually happens to the older cars as an old car may have weaker parts in its fuel system.

Another thing to remember is that one should always change his oil filter every 20,000-30,000 miles. A faulty and old filter can cause many issues in your car, including air in the fuel line.

Moreover, air can get into the fuel system if the new filter is installed incorrectly. You can change your fuel filter by yourself, but if you don’t have much technical experience, it’s better to leave it for the professionals.

What are the symptoms of having air in the fuel line?

Stalling, hiccuping, misfire, and refusal to start are common symptoms of air in the fuel line. Other issues can also be responsible for those symptoms. Visible air bubbles in the transparent fuel line indicate a leak leading to air in the system and low performance.

Understanding the symptoms of having air in the fuel system can be tricky. Why? Suppose, if there is air in your fuel system, you may have difficulty starting your car. But the same symptom can be caused by many other causes.

Check out the following points to get a clear idea about the symptoms of having air in the fuel line.


If air enters your fuel system consistently, you will experience continuous stalling of your car. The fuel injection system does not work correctly when air gets mixed with the fuel.

The engine injects a certain amount of fuel into the machine. The injector never knows if there is air in the fuel.

So, when the fuel injector injects fuel and air mixture, the amount of fuel gets lower. That way, the car starts to stall.

Many other reasons can cause stalling. If you experience stalling, you can still drive your car, but your route should be the way to the garage. Always drive a stalling vehicle in first gear and steer carefully.

A broken charging system, defective sensor, and other reasons can also cause stalling.


If a big air bubble enters the car fuel system, that may cause the engine to misfire. If you still try to drive a misfiring car, that may damage the engine.

The engine burns fuel to get energy, and as we know, the burning process must include air. The engine supplies a calculated amount of air to burn a specific amount of fuel.

But when there is already air with fuel, engines do not get the right amount of fuel or air for its running. As a result, a backfire can happen.


A car can act weird when there is air in the fuel line. Hiccuping is another common issue caused by air in the fuel line.

It is similar to an engine misfire and can occur for the same reason, although a faulty air control system is the most common reason for car hiccuping. When a car engine injects more air than necessary, hiccuping can happen.

Trouble starting the car:

When there is air in the fuel system, you can have difficulty starting your car. Starting a vehicle needs the perfect amount of fuel-air mixture. It may also have safety purposes.

If your car starts with a faulty fuel system, that may cause an accident or engine damage. However, the air in the fuel line damages the accuracy of the fuel-air mixture, which leads to a sleepy car.

What causes air in the fuel system?

Several reasons can cause the air in the fuel system. The causes can be challenging to understand if you don’t have much technical knowledge.

How can you understand that air in the fuel line is causing problems like stalling or misfiring? After opening your engine hood, you will see two fuel pipes, one is transparent, and the other is black. Usually, you can find them on the left side.

Look at the transparent pipe carefully; if you can notice any air bubbles, there is air in the fuel line. But what causes air in the fuel line? Check out the following points.

Leak in the fuel pipe:

If there is any leak between the fuel pump and the fuel transfer system, air can continuously get into the fuel line, which can significantly hamper the performance of your car.

Those leaks can be hard to find and may need experts’ help to fix the problem. Sometimes you may also need to change the fuel line pipe to make sure it happens twice.

Clogged fuel pipe:

A clogged fuel pipe can allow air to enter from the filter or weak joints of a tube. A clogged fuel pipe is easier to fix but still needs an expert’s touch.

Old or installation fault of fuel filter:

The fuel filter is an essential part of a car’s fuel system, and it needs to change after a specific time. If you use an old filter for a long time, the filter can get clogged and broken, which can cause air to pass into the fuel line.

Air can get into the fuel line if one installs a filter incorrectly. It is essential to follow the proper steps or call an expert to install a fuel filter.

An empty tank:

If there is low fuel in the tank, air can easily get into the fuel line. It is not a big issue usually, as you can fix the problem by refilling your tank. Make sure your fuel gauge is working fine.

What happens if you get air in your fuel line?

The car will act differently when the air gets in your fuel system. You can experience sets of misfires, hiccups, a hard time starting the vehicle, and more troubles like this. The overall performance will drop because of the air in the fuel line.

Most of the time, the leak will not fix automatically, or it will not come and go. So, you will have to resolve the issue with enough care so that the problem does not appear again.

How to remove air from fuel line?

To remove air from the fuel line, you need to fix the air source. If you have some technical knowledge and have your car manual with you, you can check that by yourself or even try to fix it. But the best thing will be to get a new tube that will fix the issues permanently.

Things can get pretty confusing, and if you don’t get confidence, don’t try DIY methods. Call a professional who knows what to do and how to do it. But if you choose the DIY plans, here are some steps and guides that will help you.

Check the filter:

Check if your filter is in good shape and installed perfectly. An old filter often causes air in the fuel line.

Remove the tube:

If there is a pinhole in the fuel tubes, air will get into the system. You can remove the line and look for cracks or holes. Your car manual can help you spot the tube and the way to remove it.

Look for pinhole:

After removing the tube, block one side of the pipe and submerge the line in the water while blowing on the other side. If there are any air bubbles, mark the hole spot and take steps to fix it or replace it.

Final Thoughts

The fuel line is the first thing you should check if you experience stalling, misfire, hiccups or a hard time starting your car. Visible bubbles in the fuel tube are a clear indication of air in the fuel tube. If you are familiar with your car parts, you can try to fix them alone.