5 Symptoms of a Bad or Clogged Fuel Filter (and Replacement Cost)

Last Updated on September 24, 2021

Since the fuel tank constantly attracts dust, dirt, and debris over time, the collected particles can cause harm to the fuel filter and even risk the fuel pump as well. Eventually, all these contaminants will begin to clog the fuel filter and it will not work effectively to allow enough fuel to pass through to the fuel pump.

Leaving the fuel filter of your car clogged with dirt and debris for long periods without replacement can severely affect the performance of your car engine. With a clogged fuel filter, the blockage will not allow enough fuel to pass through the filter, which may overwork the fuel pump.

To ensure your fuel filter stays clean and functional, you need to replace it according to the vehicle manufacturer’s replacement interval instead of waiting for it to wear out completely. With how inexpensive a fuel filter is, cost of replacement should never be an excuse that results in a bad fuel filter.

How a Fuel Filter Works

A fuel filter cleans the fuel of any impurities like dust particles or any form of debris present in the fuel tank that are large enough to get trapped by the fuel filter. The purpose of the fuel filter is to “filter” the fuel of such impurities before they reaches the pump.

It works similar to how an oil filter cleans engine oil and an air filter cleans the air before it gets into the combustion chamber.

The debris in the fuel tank can be in different form such as rust. This rust can form due to moisture retaining of the gas tank. Because of this rust, the fuel can get contaminated and therefore, must be cleaned by the fuel filter.

By cleaning the fuel, the fuel filter protects the engine from the potential damage which can be caused by such contamination by making sure that the fuel that goes into the fuel pump is clean and pure.

But even the best fuel filter in the world has a limited lifespan. The more contaminants it traps, the less fuel can flow through. When it gets clogged enough, you will have a fuel flow issue. You’ll want to replace the filter before it reaches that stage.

When to Replace Your Fuel Filter

The replacement interval of a fuel filter is defined by the two ways: mileage and time. Replacing the filter at a set mileage is the normal way to factor when to change your fuel filter.

For older cars and trucks, the recommended fuel filter replacement interval is usually between 20,000 and 40,000 miles. If the vehicle doesn’t get driven very often, you will still want to replace it every 2-3 years.

For modern vehicles, you can usually wait longer before replacing the fuel filter. Most manufacturers tell you to change the fuel filter somewhere between 40,000 and 80,000. But some manufacturers don’t specify an interval, have a very high interval (150,000 miles for Mercedes Benz), or even say the fuel filter doesn’t need replacement (such as Toyota).

The best thing to do is follow the manufacturer’s recommendation which can usually be found in your car manual. If for some reason you don’t have access to that, call your local dealership or simply use 60,000 miles as the change interval if you have a vehicle manufactured in the last 15 or so years.

Those with diesel engines will likely need to replace their fuel filters much sooner. For instance, GM trucks with the Duramax diesel engine need to have their fuel filters replaced every 22,500 miles for some of their newer trucks while many Ford diesel trucks have 15,000 mile change intervals.

See Also: What Happens if Someone Puts Bleach in Your Gas Tank?

Top 5 Bad Fuel Filter Symptoms

If you have lost track of both the mileage count and time passed since the last fuel filter replacement, then you should keep an eye out for the appearance of any common symptoms which may indicate that your fuel filter needs to be replaced.

The following clogged fuel filter symptoms will help you identify the problem quickly with the intention of saving you from a damaged fuel tank in the end.

#1 – Hesitation or Misfires

Once you notice that your engine randomly hesitates as you step on the gas pedal, you should consider checking the fuel filter because it may have a good amount of dirt clogging it.

Any degree of blockage will prevent the normal flow of gas into the engine leading to an unusual combustion and the ultimate reduction of the vehicles power and reaction.

In addition to hesitation, a dirty fuel filter can cause the engine to sporadically misfire, especially when accelerating. This is because there is not a steady flow of fuel due to a partially clogged filter.

#2 – Engine Doesn’t Start

Every car engine needs the combination of both air and gas to start. Therefore, without enough gas through the fuel filter, it will not start at all.

This means that you have a severely clogged fuel filter that needs immediate replacement. Otherwise, not enough fuel will ever get to the engine to allow it to start.

See Also: 5 Symptoms of a Faulty Fuel Pump Relay

#3 – Poor Acceleration

While many factors can contribute to a noticeable decrease in normal acceleration, a bad fuel filter is definitely one of them. When not enough fuel is making it to the combustion chamber, the vehicle’s computer will restrict the power output to prevent any engine damage from running too lean.

This will be most noticeable when accelerating under heavy loads such as when passing on an incline. In rare cases, the filter may be bad enough to put the car into limp mode.

#4 – Check Engine Light On

Even though Check Engine light can come on due to all sorts of problems with your car, a bad fuel filter itself can trigger it. This is usually the case with vehicles that have a fuel pressure sensor to monitor the amount of fuel going through the system.

When scanned, the diagnostic trouble code may indicate a sensor failure where in fact it is due to a clogged fuel filter. A professional mechanic should help you diagnose the main cause of the Check Engine light appearing.

Related: Code P0178 (Fuel Composition Sensor Issue)

#5 – Fuel Smell

If you notice an odor after driving that smells like you’re at a gas station, you may have a fuel leak somewhere. Once you’ve ruled out forgetting to tighten the gas cap, you need to consider other areas.

While the most common causes of a fuel leak include a bad fuel line, gas tank, fuel injector, charcoal canister, or broken spark plug, a bad fuel filter may also leak causing it to smell like gasoline. Realistically, his symptom should appear alongside another symptom to be considered.

Fuel Filter Replacement Cost

The average fuel filter replacement cost depends on the year, make, and model of the vehicle in question, whether it’s an in-line or in-tank filter, whether the part is OEM or aftermarket, and the repair shop that you go to.

A fuel filter alone is a very inexpensive part most of the time. In most cases, the filter alone can be had for anywhere between $10 and $40 although OEM parts can often push that up to $50 or more. In a few cases, the fuel filter is part of the fuel pump where the entire assembly may run you $2o0 to $500.

Usually, the labor cost will be more than the part itself. Most fuel filters can be replaced within an hour so plan on around $60 to $120 in labor. Some in-tank filters or those that are part of the fuel pump assembly may require additional labor time.

On average, the total cost of fuel filter replacement will be around $70 to $160 which includes parts and labor. As mentioned above, there are many factors that could increase this price. And don’t forget to account for taxes and fees.

If you have some automotive repair experience and a good shop manual on hand, you can save yourself a lot of money by doing the replacement yourself.