Fuel Filter: The Ultimate Guide

Fuel Filter Banner

To prevent the contaminants from reaching the engine, a vehicle’s fuel system is usually fitted with a fuel filter.

Internal combustion engines require fuel to run. This fuel needs to be clean. But that is is not always the case. Inevitably, automotive fuel will contain substances and particles, both organic and inorganic. These impurities need to be removed, or the engine’s performance and health will be affected.

Because a fuel filter performs such an important function, it is essential to understand how it works, when to tell if it is faulty, and how to obtain the right one for your vehicle. That is the reason we came up with this fuel filter guide. Reading it will help you ensure optimal performance of the engine as well as prevent damage to its parts.

In the guide, you will learn about

What a fuel filter is

Fuel filter location

Fuel filter benefits and function

How to tell if the fuel filter is gone bad

How to replace a fuel filter, and

How to buy the right and quality fuel filter

Read chapter by chapter, and learn more about this crucial part of an automotive fuel system. The guide focuses on the type of fuel filter used on road vehicles, which in some ways, is different from that of other fuel systems.

 Table of Contents

Chapter 1: Fuel Filter Definition

What is fuel filter?

How important is fuel filter to my car?

Where fuel filter is located in car engine?

What is the function of a Fuel Filter?

How does fuel filter work?

What are the difference between Fuel Filter and an Oil Filter?

Chapter 2: Types of Fuel Filters

What are the different types of fuel filter?

Chapter 3: Fuel Filter Anatomy

Fuel Filter Diagram

What is the micron rating on fuel filters?

How to measure the efficiency of a Fuel Filter?

Chapter 4: Bad Fuel Filter Symptoms

How do you know if you need a new fuel filter?

How do you check a fuel filter?

When should a fuel filter be replaced?

What are the symptoms of a bad fuel filter?

Chapter 5: Fuel Filter Replacement

How to change a fuel filter?

How to remove fuel filter?

How to mount a  new Fuel Filter

Fuel Filter Replacement Questions and Answers

Chapter  6: How to Choose a Fuel Filter

What are the factors to consider when shopping for a Fuel Filter?

Chapter 1

Fuel Filter Definition

Sample Image

What Is Fuel Filter?

A fuel filter is a simple device that is installed in a fuel system to screen out contaminants. Usually, it is a metal or plastic can that contains a filtration element. Fuel from the gas tank enters the filter and comes out clean and ready to be used in the engine.

Fuel filters have existed throughout the history of internal combustion engines. The early filters were are small plastic can. This design was suitable for the engines of that time. With fuel passing through the filter under low pressure, there was no need for an elaborate or high-strength device.

Today, the fuel filter is a slightly different design. With the introduction of direct-injected engines, there was the need for a filter that could withstand the high pressure levels in the fuel system. The modern filter is, therefore, stronger in many ways.

The outside shell is made from better material, the filtration media more robust and protected, and the whole filter assembly shielded from situations of excessive pressure by special relief valves.

These features mostly apply to the fuel filter that is fitted outside the fuel tank on the engine bay or fuel line. Commonly known as inline fuel filters, they have to withstand the different conditions, both inside and outside. Filters that mount in the fuel tank mostly have to bear the different fuel blends. They are, therefore, designed to put up with the specific environment.

How Important Is Fuel Filter To My Car?

This small device helps your car’s engine to perform at its optimum as well as last a long time. By screening out contaminants, a fuel filter acts as an engine protector.

Where Fuel Filter Is Located In Car Engine?

Location of the Fuel Filter
Source: http://19.desa-penago1.com

Because they screen the fuel that goes to the engine, fuel filters are mounted anywhere between the fuel pump and the engine. Most modern vehicles have the filter in the fuel tank, though, with some fuel pump assemblies integrating the fuel filter inside them.

In the older vehicles, the fuel filter can be found under the body, connected to the fuel line. Some will have the filter in the engine bay, where it removes contaminants just before the fuel arrives in the engine components.

A fuel filter’s location, therefore, depends on several factors. These are the car make, model, year of manufacture, and type of fuel system. Locating the fuel filter is easy. Following up on the fuel line will eventually lead you to the component. If it does not, the vehicle is probably a newer model with the filter in the fuel tank.

What Is The Function Of A Fuel Filter?

The function of a Fuel Filter
Source: http://www.truckinginfo.com

fuel filter removes impurities from fuel to protect the engine. Contaminants can get into the fuel in many ways. Mostly, it is during transportation, storage, or when filling the fuel tank that. The fuel tank itself may produce particles such as rust and paint chips. These fall off the walls and pollute the fuel.

Other impurities range from soot, dirt, sand, to mineral particles. Some are even organic in nature, such as microbial growths. Condensation in the fuel tank can also cause water in the fuel, which is unwanted, especially when your car runs on diesel fuel.

Particulate matter in fuel causes wear in the different engine parts due to their abrasive nature. In modern direct-injection engines, impurities can lead to damage or clogging. This is due to the extremely tight clearances of the injector nozzles.

In a diesel engine, water causes increased friction. Diesel serves as a lubricant for the engine parts. If it contains water, the lubricity reduces, and the engine may overheat. Water in automotive fuel can also be a corrosion agent and cause different engine components to wear out prematurely.

Other than causing wear or clogging, contaminated fuel affects an engine’s performance. The fuel will not burn efficiently, resulting in less power. When the fuel does not burn fully, there is also an increase of emissions.

When installed before a fuel pump, a fuel filter also serves to protect the pump from abrasive particles. Most pumps use a simple strainer, though. In such cases, the fuel filter is usually installed after the pump.

In summary, a fuel filter in an automobile prevents the following.

Engine wear that would be caused by abrasive particles- If the high-precision injector nozzles wear out, it results in the delivery of excessive fuel

Blocking of the fuel injector nozzles and carburetor systems- particles and organic growths can clog these engine parts, causing fuel starvation in the cylinders

Reduction of the engine’s performance- caused by inefficient combustion of fuel and brought about by impurities

Excessive smoke coming out of the exhaust- this would occur due to incomplete burning of fuel in the engine. High emissions harm the environment. In most countries, this is highly regulated

Corrosion- caused by water in the fuel. It wears the engine down and causes damage that costs the vehicle owner a lot of money

Overheating- water in diesel causes the fuel to lose its lubrication properties and results in increased friction in the moving parts of the engine

Wax crystallization this is a problem that is common with diesel fuels. Diesel contains some amounts of wax, which may crystallize in low temperatures. Some fuel filters heat up the fuel passing through them, making it more usable and preventing engine start or performance issues.

How Does Fuel Filter Work?

Direction of a Fuel Filter
Source: http://www.dieselfiltersdirect.com

A typical fuel filter consists of a filter medial and an inlet and outlet for the entry and exit of fuel. A fuel pump pushes fuel along the fuel lines at high pressure. This causes the fuel to move through the filter media forcefully. The filtration media is porous. Depending on the size of the pores, fuel flows through, while particles remain behind.

Some fuel filter types, specifically those in diesel engines, contain a mechanism to remove water from the fuel. Essentially, these filters contain a bowl at the bottom where the water that separates from fuel collects.

A drain valve allows for the emptying of the water bowl. These filters also come fitted with a water sensor to send a dashboard warning when the water needs to be drained from the bowl.

What Are The Difference Between Fuel Filter And An Oil Filter?

Besides screening unrelated fluids, the two filters are different in a few other ways. Oil filters are usually a spin-on design, while fuel filters mount using several means. There are those that install on the frame rail, or along the fuel line held by a bracket. Others mount in the fuel tank separate or as part of the fuel pump.

Oil filters are also a bigger size when compared to most fuel filters. Their design usually remains the same across different oil filter brands and different vehicles- mostly a canister with a filter media inside. The filtration media can be different types, each with own advantages and disadvantages.

Most fuel filters, especially gasoline filters, are a smaller size than oil filters. The designs are a wide range, too. Unlike oil filters that mount in the engine bay, fuel filters can be positioned in different places between the gas tank and the engine. As a result, fuel filters exist in various shapes, sizes, and other construction differences.

To better understand how a fuel filter works, it is essential to have an idea of the different types of these filters. That is what the next topic entails.

Chapter 2

Types of Fuel Filters

Different Types of Fuel Filter

A fuel filter can be primary or secondary, canister or cartridge, and spin-on,in-tank, or inline. As we have seen, the design and mounting style depends on several factors. These include the vehicle type, model, and the year of manufacture. The type of fuel system, too.

Newer vehicles have fuel filters that are different than those of the earlier days, both in design and position in the vehicle. While older carbureted vehicles have the filter anywhere along the fuel line, most modern automobiles have the filter inside the fuel tank.

Diesel engines also have fuel filters that look and function differently from those used by vehicles that run on gasoline. Diesel filters are bigger and mostly bowl-shaped Depending on the fuel system used, a vehicle may use a primary filter or both primary and secondary fuel filters.

What Are The Different Types Of Fuel Filter?

Below are the different fuel filter types explained.

The Primary Fuel Filter
Source: http://www.oshkoshequipment.com

Primary Fuel Filter

This type of fuel filter is commonly used in diesel fuel systems. Its function is to filter out most of the contaminants- the large particles and particularly water and wax. Positioned on the vacuum side of the fuel pump, the primary filter also protects the pump from particulates that would cause it damage or wear.

Primary filters are usually less restrictive. This is because they often precede the secondary filters in the fuel system and do not need to capture the finer impurities. These filters mostly remove particles that are larger than 10 microns.

Secondary Fuel Filter
Source: http://www.silverfoxtractorspares.com

Secondary Filter

Also used in the filtration of diesel fuel, secondary fuel filters serve to block the finer particles. A secondary filter is, therefore, fitted with a tighter media or one with a high micron rating. In terms of position, these filters mount on the pressure side of the fuel pump, which is usually nearer to the engine.

Secondary filters do not remove water from fuel, only the smaller particles that are less than 10 microns.

Fuel filters are not complex devices. They only have a few parts that make them up. Gasoline fuel filters can be said to be the most basic. They do not usually feature a mechanism to extract water from fuel, which means a less complicated construction.

Some fuel systems use both a primary and secondary filter to clean the fuel going to the engine. Others use only one fuel filter, the primary filter that removes particulates, precipitates, wax, and water from fuel. Still, some systems utilize a normal filter and the option for an additional water separator.

Gasoline systems usually depend on a single filter. Gasoline is a cleaner fuel than diesel and the reason why it does not require double filtration. Diesel, on the other hand, naturally contains more impurities, specifically water and excess wax.

To make diesel more usable, manufacturers often install a primary filter to remove particles, water, and wax and a secondary filter to catch the remaining pollutants. It can also be a single filter that comes with a mechanism to remove water and cause it to deposit into a bowl within the filter housing.

The Canister Fuel Filter
Source: http://3.hpkzl.visoul.de

Canister Fuel Filter

This is a type of filter that features a canister like shell with the filtration element inside. Most filters are of this type. The housing can be plastic or metal depending on several factors. Canister fuel filters are said to be less friendly to the environment. When their lifespan is over, the whole device needs to be removed and thrown away.

Cartridge Fuel Filter
Source: http://autokrafters.com

Cartridge Fuel Filter

This form of fuel filter features a cartridge consisting of the filtration media, structural components, and other essential fuel filter parts. The only thing that these filters lack is the outer shell. Instead of the metal or plastic housing being part of the filter, it is a separate component that mounts on a mating surface on the vehicle. It can be used again and again, with only the cartridge being the disposable part.

Cartridge fuel filters are an environmentally friendly option. With fewer metal or plastic parts to throw away, changing this type of filter is less impacting on the surroundings. That is when compared to the canister type of filter, parts have to be manufactured and thrown away to replace a bad filter.

Spin-On Fuel Filter
Source: http://shop.gopurepower.com

Spin-On Fuel Filter

As the name suggests, this is the type of filter that uses threads to mount on the vehicle. Spin-on fuel filters are usually installed in the engine compartment. Their major advantage is that they are easy to replace. The process only involves unfastening the damaged filter and fastening a new one in its place. In addition to the procedure taking only a short time, almost any vehicle owner can perform it.

Inline Fuel Filter
Source: http://summitracing.com

Inline Fuel Filter

These are mounted along the fuel line, between the gas tank and the engine. Because of the location of the fuel lines, these fuel filter types are usually found underneath the vehicle. The filters feature an inlet on the fuel pump side and an outlet on the other. The two openings connect to the hoses or tubes that make the fuel line, and the device is held in place by a metal bracket and plastic safety clips.

In-tank Fuel Filter
Source: http://partsreloaded.com

In-Tank Fuel Filter

These are mounted in the gas tank, away from view. Most modern automobiles use in-tank fuel filters. The filter can be separate or integrated in the in-tank fuel pump. A disadvantage of these types of filters is their inaccessibility, which makes them difficult to service. When part of the fuel pump assembly, in-tank fuel filters cannot be replaced separately. That means a more costly replacement when you have to change a clogged or damaged filter.

Having looked at the types of fuel filters, we can now move onto the inside of the filter and see what these components consist of. The next chapter delves into the fuel filter parts, with a description for each.

Chapter 3

Fuel Filter Anatomy

Fuel Filter Anatomy

Fuel filters come in different designs, shapes, sizes, and internal constructions. The kind used in a vehicle depends on its make, if modern or older model, and the type of fuel system. Differences occur in the kind and size of contaminants filtered, the fuel being filtered, the filter’s location on a vehicle, mounting style, and so on. In this section of the fuel filter guide, we will look at the fuel filter parts in a typical gasoline and diesel fuel filter.

Fuel Filter Diagram

A gasoline fuel filter is different from the type that cleans diesel, both in the parts and working. Diesel fuel filters and designed to remove water. Gasoline filters do not. Because diesel contains more impurities than gasoline, diesel fuel systems mostly use two filters, one to trap the bigger debris and water, and the other the finer particles.

Fuel Filter Diagram
Source: http://levintire.blogspot.com

What Are The Parts Of A  Fuel Filter?

A typical spin-on fuel filter will have these components.

Base Plate- the part at the end of the filter housing where device mates with the mounting assembly. The base plate provides the installation interface, prevents fuel leaks, and hold in the pressure inside the filter. The baseplate also contains the threads to mount the filter.

End Cap- the supporting structure that holds the filter media in place. Attached to the filtration media using adhesive, the end cap also prevents leaks.

Center Tube- the center tube supports the filtration and prevents it from collapsing inwards. Other than being a structural component, the tube acts as the outlet for filtered fuel. To withstand the differential pressures created in the filter, manufacturers make this part from sturdy material, usually steel.

Filter Media- as the name indicates, this part is the membrane that traps particles or water and other particulates or precipitates. It can be cellulose or a synthetic material. A filter media is usually pleated to increase the surface area on which filtration takes place.

Parts of a Fuel Filter
Source: http://nivaforever.wordpress.com

Compression Spring- provides compression force that holds the internal components in place under varying differential pressures.

Drain Valve- when present in a fuel filter, the drain valve provides a means for fuel to bypass the filter media. It allows the fuel from the tank and straight to the engine unfiltered. This happens when the filtration media is too clogged to allow fuel through.

Water Sensor- a fuel filter water sensor is usually fitted in the filters that remove water fuel. When the water from fuel has reached a critical level, the sensor sends a signal that lights up a dashboard signal. This allows the driver to tell when the water Ned’s to be drained.

Canister- this is the housing that protects the internal components of the fuel filter. Made from steel, the canister contains the pressure inside the filter and prevents it from bursting.

What Are The Different Types Of Fuel Filter Media?

Fuel filters use different materials for the filtration media. They can be natural or synthetic. Each has its upsides and downsides. Natural materials include paper that is made from cellulose, a plant-based material.

Cellulose media can be treated to give it water filtration capabilities. This allows filters made from cellulose to be used as primary fuel filters. Synthetic materials include glass fibers, sintered bronze, ceramic, and nylon. Here, we will look at the most used media in today’s fuel filters.


Cellulose media is made from a special type of paper made that consists of plant-based fibers bound with resin. With relatively large pores, this type of filtration media is unsuitable if extremely fine particles are to be trapped. Cellulose fuel filters are mostly used in gasoline and diesel fuel systems.

Cellulose is less restrictive and will pass adequate amounts of fuel even when the filter is clogged to a certain level. Because of this property, these filters have a longer service life. When impregnated with a special material, cellulose can be used as a primary filter in diesel fuel systems to remove water and the coarser impurities.


A type of synthetic filter media, microglass offers better filtration for the finer impurities. The spores are smaller and more uniform, which makes the media more restrictive. That also means the lifespan of a microglass fuel filter will be shorter than that of cellulose media.

Microglass fuel filters are suitable for the filtration of biofuels, low-sulfur diesel, and ethanol blended gasoline. These filters offer better engine protection but cost ore than cellulose filters. When clogged, they can cause a strain on the fuel pump and cause it to wear down quickly.

What Is The Micron Rating On Fuel Filters?

When used for a fuel filter, micron rating indicates the filter’s ability to capture contaminants of a specific size. A micron rating of 10 microns means the filter removes particles that are 10 microns and above, while a 5 micron rating shows a filter capable of trapping impurities of size 5 microns or larger. A filter’s micron rating basically refers to the size of the pores in the filter media. The larger the openings, the higher the micron rating value.

Micron rating can be nominal or absolute.

Nominal Micron Rating indicates the percentage of specific particle size that a filter can remove. Not useful on its own as it does not explain how efficiently a filter does that.

Absolute Micron Rating- indicates how efficiently a filter removes particles of a particular size. Usually derived from tests, which can be a single pass test or multi-pass test. Absolute micron rating is more useful than nominal rating when describing a fuel filter.

How To Measure The Efficiency Of A Fuel Filter?

This refers to a filters particle retention level. It is a measure of the particles captured Vs. the particles that are present in the fuel. The value for efficiency is usually used together with the value for micron rating. A filter whose efficiency is 98% and micron rating  5 microns removes 98% of particles that are 5 microns in size and larger.

Fuel filter efficiency is usually described as a Beta ratio or percentage. Here is a fuel filter micron rating chart showing values for Beta Ratio and efficiency levels.

Beta ratioNumber of particles of specific sizes that pass through (out of the total)Filter efficiency
21 out of 250%
101 out of 1090%
1001 out of 10099%
2001 out of 20099.5%
10001 out of 100099.9%

The modern fuel filter comes with a range of features and specifications to improve its service. However, they cannot last the lifetime of the vehicle. Eventually, the filter media clogs up with dirt and starts to show signs of damage. The next chapter explains these symptoms.

Chapter 4

Bad Fuel Filter Symptoms

Bad Fuel Filter Symptoms
Source: http://arrowheadmbsprinter.com

How Do You Know If You Need A New Fuel Filter?

After a fuel filter has trapped debris for several thousand miles, it may start to fail. That often happens when particles clog most of the pores of the filtration media, leading to a restricted flow of fuel. The filter’s efficiency then drops, and the effects start to show in the engine and other parts of the fuel system. If installed on the suction side of the fuel pump, a bad fuel filter may even affect the pump.

Fuel filter failure does not only result from clogging. It can be damage to the filter media that allows too much fuel through (and too many impurities). Both scenarios are not desirable in a vehicle’s fuel system. Contaminants cause wear or clogging of some engine parts while too little fuel may lead to loss of power, burnt out pistons, and overheating problems.

Luckily, a failing filter usually produces signs. Although no too apparent, bad fuel filter warnings can help you restore engine performance. Here is a look at some of the signs that indicate fuel filter problems.

How do you check a fuel filter
Source: http://blog.pvusedcars.com

How Do You Check A Fuel Filter?

Faulty fuel filter symptoms may indicate a problem such as clogging or filter element damage. However, they are not a final word, and you may need to examine the filter itself. How do you check a fuel filter for damage or clogging? Some fuel filter types feature a plastic housing that is see-through. Others will have a window to allow you a view of the internal components.

By observing the media, you can tell how severely the pores are blocked. If the media is discolored and covered by visible debris, consider replacing the fuel filter. For some filters, this can be as simple as changing the cartridge. For others, it means replacing the whole device.

Another way to tell a bad fuel filter (and the one that your mechanic would use), involves measuring the fuel pressure. This is done using a pressure gauge. If the filter is severely clogged, the pressure gauge will register a substantial pressure drop.

A less conventional but still useful method entails observing the flow of fuel when the engine is running. To carry out this test, you disconnect the fuel line that goes to the filter but only on the engine side. Someone then starts and runs the engine, while you observe the flow of fuel out of the filter.

This fuel filter test can give you an idea of how restrictive the filtration media is. If there is not sufficient flow of fuel, it means the filter is clogged. You now know what the problem is that is causing symptoms such as power loss, poor starting, and more.

When Should A Fuel Filter Be Replaced?

A bad fuel filter requires replacing. While some people might try to fix a damaged filter by cleaning it, it may not be a good idea. Besides, most fuel filters are not costly devices. They also last a long time, and installing a new one cannot subject you to unhealthy expenses. How do you replace a bad fuel filter? The answer to that question is in the next chapter.

What Are The Symptoms Of A Bad Fuel Filter?

Engine light turns on
Source: http://www.edmunds.com

1. Check If The Engine Light Turns On

Some vehicles come with a dashboard indicator light that is triggered by changes in fuel pressure, lean fuel, engine misfire, and several other issues. A clogged fuel filter causes a reduction of fuel pressure in the system. This is the problem that is picked by the sensors to indicate a problem with the engine.

Because checking engine light can be turned on by a range of issues, it is recommended to have the computer scanned for problem codes. That would help you to determine the exact problem that is activating the check engine light.

2. Reduced Power When The Engine Is Stressed

It is one of the major clogged fuel filter symptoms. When the filter is blocked, it passes minimal fuel. This results in fuel starvation, especially during times when the engine is too demanding. This can be when going uphill, loaded, or when accelerating. The increased need for more fuel cannot be met, which results in the driver experiencing loss of power.

If your vehicle feels somewhat sluggish when the engine is under stress, you may want to check the fuel filter. While reduced engine power can be a sign of other problems such as failing fuel pump, a clogged filter should be one of the components to suspect.

Can A Clogged Fuel Filter Cause A No Start?

If an already clogged filter is left on a vehicle, it reaches a point where the flow of fuel is substantially reduced. When this happens, you may have trouble starting the vehicle. The engine requires some amount of fuel to crank up. When that amount is unavailable, the process cannot begin.

It is good to note that a clogged filter is not the only cause of starting issues in a vehicle. Several other components can lead to the problem. These include a dead battery, a bad starter motor, starter relay or solenoid, and a few others. It is, therefore, advisable to ensure that the other parts of the starting system are working correctly.

What happens when the filter is substantially clogged, but not too severely?

When driving at high speeds, the fuel pump pushes the fuel through the filter more forcefully. The increased pressure is then enough to overcome the restriction of the filter media. As a result, there may be no noticeable loss of engine power.

When driving slowly, the opposite happens. The fuel pump does not pump fuel through the filter as hard as when driving fast. This cause the filter media restriction to the flow to be felt. It is one of the most common clogged fuel filter signs when driving normally.

What happens when fuel filter is severely clogged?

This mostly happens when the filter is severely clogged. The available fuel is then enough to start the engine but inadequate to keep the vehicle going. As soon as the car picks up speed and requires more fuel, the filter fails to cope, and the engine stops running.

During such situations, you may find that you can still crank up the engine. This happens because there is always some residual fuel in the fuel lines, plus the little amount that flows through the filters. However, once the engine has started to turn, the demand cannot be met anymore, leading to a stall. Changing the fuel filter would fix the problem.

Can a clogged fuel filter cause rough idle?

The engine stutters when idling. The tachometer may also have its needle move up and down erratically. These symptoms indicate a bad fuel filter, especially one that has clogged and not allowing enough fuel to flow to the engine. The inconsistent supply of fuel is what would cause the vibrations of the engine when idling.

Can a fuel filter causes misfire
Source: http://www.jeepz.com

Can A Fuel Filter Cause Misfire?

Yes, If the filtration media is blocked by particles, you may find that the engine misfires occasionally. This may not happen when the engine is idling unless the clogging problem is extreme. Mostly, it occurs when going uphill or accelerating, and the demand for fuel is high.

Should you notice the vehicle jerk a few times when the need for gas increases, it is advisable to check if the fuel filter requires replacing. This can be if it is several ten thousands of miles since it was installed. Also, if you have been driving around on a near-empty gas tank.

3. Fuel Pump Failure

A clogged filter restricts the flow of fuel. This causes the fuel pump to work harder. When the pump has to force fuel through this kind of filter every driving time, it is likely that it will break down too soon. The increased strain wears down the various parts of the pump.

If the fuel pump is damaged, there is a reason to suspect a clogged filter to be the cause. This is especially if it broke down earlier than its expected lifespan. In such cases, changing the filter may not help much. Only a fuel filter replacement would offer a lasting solution.

4. Hard Starting

If your vehicle does not start easily, it could be that debris is starting to build up on the filtration media of the fuel filter. A partially clogged filter would cause a slight restriction to the flow of fuel. This results in an inconsistent supply of fuel to the engine, and the reason for the hard starting.

A clogged fuel filter is not the only problem that would cause starting difficulties. However, the filter is an easy and more probable place to start your diagnosis. Most vehicle owners experience this when the fuel filter has neared the end of its lifespan.

Chapter 5

Fuel Filter Replacement

The Fuel Filter Replacement
Source: http://www.carbibles.com

Fuel filters exist in different types and designs. They are also found in different locations on a vehicle, not to mention the unrelated mounting styles. All these variations make it impossible to have a replacement procedure that fits all filter types. Some are not even serviceable, hidden in the gas tank and within the fuel pump.

When compared to those that clean diesel, gasoline fuel filters are easier to replace. Gasoline filters are also usually smaller and often single filters in a fuel system. On the other hand, diesel fuel filters are larger and mostly two in a fuel system.

For these reasons, our fuel filter replacement process will focus on the gasoline fuel system and the in-line fuel filter. It is one of the most common fuel filters in today’s automobiles. The filter is also among the simplest to replace. Let us get started

How To Change A Fuel Filter?

How to change a fuel filter
Source: bmwguide.net

Things you will need:

The new fuel filter, screwdrivers, open-end wrenches, rag, a bowl to catch the fuel that might spill out, piece of cloth, and protective gear such as goggles and gloves. You will also need a jack and jack stands.

Precaution: gasoline is highly flammable. Work in a well-ventilated place and keep items that may produce sparks or flame away.

Relieving Pressure and Expelling Fuel

Step 1.

Find the fuse box and remove the fuse. This will disconnect the power supply to the fuel pump and relieve the pressure in the fuel lines. To locate the fuse box, use your car’s manual, or look up the manufacturer’s website.

Step 2.

Secure the vehicle by ensuring it is not in gear. For those that use automatic transmission, it should be in park. If a manual transmission vehicle, that means ensuring the car is in neutral and with the parking brake engaged.

Step 3.

Start and run the engine for a few minutes. Doing so serves to expel any remaining fuel as well as release pressure from the fuel lines. Because the fuel pump is not active, this should happen within a minute or two.

Step 4.

Switch off the engine. Re-insert the fuse. Leave the engine turned off and the vehicle secured.

How To Remove Fuel Filter?

How will you remove a Fuel Filter
Source: http://www.f150forum.com

Step 5.

Find and disconnect the negative terminal of the battery. It is a safety precaution to prevent the engine from starting while working underneath the vehicle. Clamp it away safely.

Step 6.

Now, find the position of the fuel filter on your vehicle. In our case, it should be located along the fuel line under the vehicle. For easy access, Jack up the vehicle, taking care to use jack stands for safety reasons.

Step 7.

Place a container underneath the fuel filter to catch any fuel that may come out of the fuel lines or filter. Next, remove the two plastic clips that secure the fuel filter. Use a screwdriver to do that. The clips should come out without difficulty.

Step 8.

Slide the fuel lines on either side to disconnect them from the fuel filter. You can use a fuel line disconnecting tool to make this easier. Be sure to direct the fuel lines at the container so that spilling gasoline may collect there.

Step 9.

With the fuel lines out of the way, you can now remove the fuel filter. Slide it out of the bracket holding it. Check to see if there is a bolt or bolts to remove.

How To Mount A  New Fuel Filter

How to mount a new fuel filter
Source: youtube.com

Step 10.

Examine the new filter to ensure it is the right one for your vehicle. Check to see that the filter is identical to the old one both in the inlet/outlet diameters, size, and other design features.

Step 11.

Insert the new filter in the bracket and replace the fuel lines. Replace the plastic clips that hold the filter in place. These clips can break easily. If that happens, you may need to replace them.

Step 12.

Lower the vehicle and reconnect the negative terminal of the battery. Start and run the engine and run it for not more than a few minutes. Check to see that there are no leaks in the newly installed filter.

Fuel Filter Replacement Questions And Answers

This is a compilation of the common questions car owners ask when looking to replace a fuel filter.

How Long Does A Fuel Filter Last?

Fuel filters can last for between 30 000 to 50 000 miles. That is around two to three years. How often to change a fuel filter depends on several factors, though, such as how clean the fuel is, type of fuel, and whether it is a primary or secondary filter.

It also depends on your driving habits. If you are fond of driving on an empty tank, the fuel filter cannot last its lifetime. Sediments usually collect at the bottom of the tank. Using the last fuel in there means those impurities are reaching your fuel filter and clogging.

How Much A Fuel Filter Cost?

Fuel filter replacement cost varies, but not immensely. Most filters are not costly to replace. The filter itself mostly costs between $15 and $150, on average. Labor costs are slightly higher than this, costing between $50 to almost $200.

How Often Should Fuel Filter Be Changed?

If the fuel filter has lasted for or more than two years, it could be about time you replaced it. Also, if you start to see the symptoms of a bad fuel filter described in this guide.

What Are The Effects Of Driving Is A Bad Fuel Filter?

A damaged or clogged fuel filter starves the engine of fuel. It may also deliver contaminated fuel. This has several effects. Apart from the loss of power, it could cause damage to the engine parts. Eventually, it would reach a point where the engine fails to start or stalls in the middle of a journey.

Can You Clean A Fuel Filter?

If it is a metal mesh, it can be cleaned and reused. If made of paper or nylon filtration media, the best option would be to change it.

Owning a vehicle for more than two years and using it constantly means you will have a fuel filter to replace. Regardless of whether you change the filter yourself or take the vehicle to a mechanic, it is necessary to have the right filter installed.

Being careful with what fuel filter you buy can save you the stresses of having to replace it too soon, or poor engine performance. The next chapter talks about how you can purchase a quality fuel filter.

Chapter 6

How To Choose A Fuel Filter

New Fuel Filter
Source: http://multintionalparts.com

With the many fuel filter types available, it can be daunting to choose the kind that suits your vehicle. Usually, the make, type, and year of manufacture of your vehicle can guide you towards deciding a matching fuel filter. But that is not always enough. There are other considerations to make and which can mean the difference between the best fuel filter and an inferior one.

The salesperson at the auto shop can help you to buy a filter for your vehicle. However, they may not match every feature. Websites, too, may offer a means to narrow down your choices but the type of fuel filter that you settle for will depend on your specific preferences and requirements.

To help you decide on the fuel filter to buy, we compiled a list of the factors to consider.

What Are The Factors To Consider When Shopping For A Fuel Filter?

Factors of New Fuel Filter
Source: http://www.mecatech.co.uk

Fuel Type

While most fuel filters are compatible with a wide range of fuels, knowing what works best can help you make the right choice. Diesel fuel filters are mostly different from those of gasoline. Diesel requires a filter that can remove water, while gasoline does not. You may also want a fuel filter that can withstand high pressures if the engine uses diesel fuel.

Fuel Flow Rate

It is important to determine the flow rate of the fuel system used by your car. Then, you can choose the kind of filter that suits it. Some filtering media are too restrictive and will not pass sufficient amounts of fuel, especially when they begin to clog. A less restrictive filter will, on the other hand, cope with a high flow rate fuel system.

Micron Rating And Efficiency

Fuel filters come with different micron rating. A low rating means the filter captures the finer contaminants more efficiently and offers better protection to the engine. However, such filters have shorter lifespans. After several thousand miles, a low micron filter may become too restrictive and stress the fuel pump.

Filter Type

There are in-line fuel filters, in-tank filters, primary and secondary filters, cartridge or spin-on. Before you go out shopping, understand the type that you intend to buy. You will need to replace the old one with a similar type, or you will encounter installation problems. For an in-tank fuel filter, you may need to purchase it together with the fuel pump as one piece.


Fuel filters come in different sizes, shapes, and so on. The type you buy should match the one used in your vehicle. Otherwise, you may experience compatibility issues where the new filter does not fit its mounting place. For spin-on filters, the threads should match. Similarly, the inlet and outlet diameters of in-line filters should match that of the fuel line.

The Filter Media
Source: http://www.awapaper.co.jp

Type Of Filter Media

Fuel filter media usually come in two main types; natural and synthetic. Cellulose falls in the natural category, made from plant fiber. Cellulose is mostly preferred for its minimal restriction to the flow of fuel. It does not strain the fuel pump, which means a longer lifespan for the pump. The fuel filter, too, since it does not clog easily.

Synthetic fuel filter media is mostly glass fibers. This type of media screens out the finer particles and offers better engine protection. But then, that also means a filter that will not last for long. Also, a filter that stresses the fuel pump over time to cause damage. Other synthetic fuel filter material, other media include sintered bronze, nylon mesh, and ceramic material.


After all the other considerations, it is essential to choose fuel filter brands carefully. You want a filter that will deliver clean fuel to the engine- and in the right amount. A filter that will offer a decent service life, too.

To ensure all that, choose a trusted manufacturer, a company that supplies quality fuel filters. You can gauge that from the features of their fuel filters, the online and offline reputation the company has earned, and so on. With the best fuel filter brand, quality is assured.

Fuel Filter Price

Most fuel filters are not costly vehicle parts. When buying them, price may not be a major factor to consider. However, look for a filter that is not too cheap. Such a filter would most probably lack features to ensure efficiency or long life. As is the case with other vehicle parts, a fair price is what you should go for.

When buying a fuel filter for your vehicle, it is essential to take into account every consideration. These parts of the fuel system last more than a year on your car. You, therefore, want to get it right the first time. That means choosing carefully to ensure only the best fuel filter for your type of vehicle, fuel system, and other aspects.


The automotive fuel filter is one of the most crucial components in a fuel system. By  capturing contaminants, the filter helps to ensure optimal engine performance. It also protects engine from various forms of wear and damage. To ensure that the fuel filter performs these functions, it requires wide knowledge about how it works. Also, about how to tell when it starts to fail.

That is the knowledge this fuel filter equips you with. After reading through every chapter, you can now ensure your car’s engine remains protected from impurities at all times. You can tell when the fuel filter needs changing and how to do it yourself without outside professional help. And when you have to purchase a fuel filter, how to select the right one for your vehicle.

A car fuel filter is a simple component. However, that does not make it any less important. It requires proper maintenance, which means timely replacements, among other practices. If cared for well, the fuel filter can help you to have a nice experience with your car, SUV,truck, or even bike.

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