What are the Symptoms of Bad or Failing Fuel Filter and How to Replace It

Brandon Trenton

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Bad fuel filter symptoms and how to replace it

The engine of a car or any other automobile is very fragile and requires specific qualities of fuel, oil, and air to operate at its peak. If there is any unfiltered fuel in the engine, there can be some severe damage, which can often lead to engine stalling. Similarly, air going into the engine for combustion needs to be filtered to improve the performance and reduce pollution levels.


Different Types of Filters

Usually, every car is integrated with four different filters.

Fuel Filter

A fuel filter is installed to remove any impurities that might have entered the fuel. If these impurities enter the engine, there can be several issues like misfiring of the cylinder, engine stalling, and even damage to the piston head. To avoid such a scenario, a fuel filter is necessary.

Air Filter

During the combustion process of an engine, the fuel requires some amount of oxygen to ignite. To facilitate this, there are air filters that assist in purifying the air particles utilized by the mechanism. Air filters require regular maintenance. Correlatively, it is conveniently possible at home.

Oil Filter

In many vehicles, there is more than one air filter; this is because of the different types of oil used in different parts of the car, such as brake oil, engine oil, and gear oil. In some oil-cooled engines, the need for the oil filter is amplified.  All of these filters work to optimize the car’s performance.

Cabin Filter

This filter is responsible for the air going into the passenger cabin, via the air vents installed inside. Cabin Filter does not affect the performance of the engine directly. Without an air filter, the quality of air would be poor. Significantly, it affects the performance of the AC, which in turn would pull more power from the engine, thereby reducing the fuel economy.


The Layout Of A Fuel Filter

The positioning of Fuel Filter

The fuel filter is located at the fuel line, slightly before the fuel injector, or a carburetor in the older vehicles. Recently many car manufacturers have started positioning the fuel filter in the tank right before it enters the fuel line. This is not a universal practice, though.

Formation of Paper Cartridges

The filter is a formation of paper cartridges that screens out the foreign particles. These particles may include debris, sand, or even metal particles. The fuel passes through the filter, and any impurities that might plague the fuel are left in the filter itself. When the car is being serviced, take a look at the condition of the filter to get an idea of the impurities in the fuel.

The paper cascading is simply a porous material that allows the liquid particles to pass through it while removing the solid particles like paint chips, metal, and dust particles.

Built as Cylindrical Containers

Usually, the fuel filters are built as a cylindrical container, but their shape can vary. In several diesel engines, the filters used are in a bowl shape. The different forms are a result of the positioning of the filter and the design of the cascade.

Fuel filters need to be replaced at regular intervals. However, some manufacturers do use filters that are designed to be reused after servicing.


Symptoms Of A Fuel Filter In A Poor Condition

To know the condition of the fuel filter, you need not be a mechanic. All you need is to observe the signs your car is giving you. In case of a filter, the vehicle shows these following indications:

Whining Noise

This is the first sign from the car in case of a clogged fuel filter. Initially, it is a random whining at slightly higher speeds, but it soon transpires into a continuous whining even during idling. Avoid delaying the replacement of a fuel filter.

Lack Of Engine Power

This is the second symptom. If your fuel filter is clogged, it will not allow the required amount of fuel to enter the combustion chamber. Because of this, the amount of fuel in the combustion chamber is less, leading to a lean mixture. Hence during the first couple of years, you might feel the engine lacking in power.

Engine Misfires

This would have happened in your car quite a few times. The engine runs in cycles, which consist of a set number of strokes, depending on whether the engine is a single, double, or a four-stroke one. Now, if there is a misfire, you would feel a jerk and a sudden loss of power for a split second. This happens because, in the combustion chamber, there is enough fuel for ignition, but not enough for a powerful explosion. Because of this, the air in the cylinder will not burn completely.

Engine Stalling

This is the final sign that your car’s fuel filter has given up. This is the stage when the filter is too clogged to allow any fuel to pass through the engine.  It is where your engine enters the seizing process. Now you’re running your vehicle at a risk that the engine can seize at any moment.

Any vehicle drives exceptionally with the unison of each of these performing parts. Even with a fault in a single component, the entire performance can decline. While you don’t need to be a professional, you should understand the tune of your car. It will always provide you with hints. Fuel filters are one of the primary components in this cycle, and if there is an issue with it, try to replace the filter as soon as possible.

Focus on the first few symptoms, and take a look under the hood; otherwise, you can always go to your trusted mechanic. Consider the engine misfire as a final warning and do not neglect it. Because, if the engine is misfiring, a complete stalling is not far away.


Can I Replace A Fuel Filter In My Car

Well yes. You can change the fuel filter of your car at home, conveniently. It is not rocket science, but you should take proper precautions and diligent measures. Here are the things to consider before you replace the filter.

Be Sure of Where the Fuel Filter is

Many cars have their fuel filter in the engine bay and are easily accessible. However, in many of them, these filters are located towards the underside of the car or inside the fuel tanks. In either of these two cases, do not attempt to do the replacement at home as it requires more than just replacing the filter.

Understand the Mechanism

This is necessary, as different car manufacturers use different types of locking mechanisms for the filter. Understand these mechanisms and know how they work to remove the filter with ease without causing any damage to the fuel line or any other part.

Do Not Remove the Filter Until the Fuel Lines are Empty

The fuel lines carry fuel under high pressures. And if the engine has been running, do not attempt to remove the filter, as the fuel would be highly pressurized. Under the pressurized condition, it would be nearly impossible to stop the flow of the fuel until the fuel lines are empty.

Bleed the Engine After You Have Replaced the Fuel Filter

Bleeding is essentially the part when you remove the air from the system and fill it with the fluid that is required.


The Process Of Fuel Filter Replacement

Now once all the above precautions are considered, observe the following steps that will guide you while changing the fuel filter.

  • Ask your dealer which type of filter is available in the car model you have. Get the new filter from the dealership, and any of the tools you might not have.
  • Now look for the fuel pump, which might be attached to the fuel pump or somewhere around it. The user manual of the car might have information regarding this.
  • Disable the fuel pump to relieve the pressure from the fuel lines. This might take a while, so be patient. Make sure the engine is turned off, and parking brakes are applied.
  • Now the filter might be secured to the fuel lines using a locking or clamping mechanism. Understand this mechanism and remove the filter.
  • Now place the new filter in the same position and lock it using the same mechanism. Make sure the filter is completely secured.
  • Now switch the engine on and check for any leaks. If there aren’t any, then congratulations, you have successfully replaced the fuel filter of your car.

Once you are done with the replacement and your car is working well, check the old filter. Cut it open and take a look at the condition of the filter, and note the time it took to get to such a state. This will give you an idea of how long the filter lasts until it should be replaced.


Take Deliberate Care of Fuel Filters

Fuel filters are one of the most necessary parts in the vehicle and do not disregard any signs that might suggest an issue your car is facing. The car might be running, and you might feel like it is working well, but it is not and might stall soon. To avoid any such mishap, keep an eye out for the car’s performance and the way it is behaving while driving.

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