For most people who aren't considered car people, the fuel filter is a part that we never think about. It does play a vital role in the function of your vehicle however because it prevents dirt and debris from circulating through your fuel lines which could greatly impact the overall performance of your vehicle. Unfortunately, because the fuel filter isn't out in the open where everyone can see it, most drivers don't give it a second thought and will often forget about it entirely. That means that when the fuel filter starts to fail or there's another problem with it, it's not always the first thing that you think of.
The fuel filter in your car looks like a small cartridge, slightly bigger around than a can of soda. Inside of it there's a filter paper that allows fuel to pass through but stops contaminants from getting into the system. You can consider it not unlike a water filter at home in that the job it does is simple but very important for keeping things clean and running smoothly.
There are some clear signs that you can be on the lookout for to let you know if your fuel filter has a problem. Additionally, the more you know about your filter the easier it will be for you to give it a check when you're doing some routine maintenance to see if it is working properly or if it needs to be cleaned or replaced. With that in mind, here are some of the symptoms that you can be aware of that will let you know you're having a problem with your fuel filter and you're going to need to get it checked out.
Signs and Symptoms of a Bad Fuel Filter
Anytime something goes wrong in your vehicle there can be several potential causes for it. With that in mind, if you were experiencing several of these symptoms in your vehicle, that likely means the problem you're having is with your fuel filter and not something else. Still, if you're not sure, the best bet is always to go to a mechanic and get it checked out.
If you find that your engine is misfiring at random times, especially if you are heading up an incline or towing something heavy behind you it's possible that a clogged fuel filter is the cause. When your filter is clogged it prevents the right amount of fuel from flowing through the lines and getting to the engine. This is most likely to happen in situations when your fuel demands increase, like we said when you're towing or going uphill. If the fuel injector can't spray the correct amount of fuel into the combustion chamber because of a clog, then you'll likely have these issues with misfires, as well as a stuttering or shaking vehicle. This is all due to the incorrect amount of fuel being injected for the combustion reaction to occur, or because it's happening at the wrong time because your car is struggling to produce the fuel necessary for the reaction to occur.
Different from a misfire, engine stalls are exactly what they say, when the engine seems to just crap out on you. Although there are a number of things that can cause your engine to stall, a clogged fuel filter is actually one of the more common ones. Because your engine is not getting the fuel it needs to function properly, and will continue to not get the fuel it needs because of the clog, if you're having frequent issues with the engine stalling out on you it is very possibly caused by a clogged fuel filter.
Bad Gas Mileage
It should come as no surprise that your gas mileage is going to suffer if your fuel filter is clogged. Some people might think that a bad fuel filter would actually increase your gas mileage since you'd be using less fuel but that's not actually the case. What happens is that, since the fuel is struggling to get through the line, the engine increases demand for fuel. That will cause it to pump faster, and you'll end up wasting fuel more quickly as a result.
Another good sign that you're having an issue with your fuel filter is when the vehicle struggles to start or will not start at all on the first one or two tries. Because your vehicle can't start until the fuel hits the combustion chamber for that very first spark, if your fuel filter is so clogged that the fuel can't get through the line properly then your combustion reaction won't be able to initiate and your engine will not get started right away as you'd expect it to.
This likely means that you will have to turn the key in your ignition several times to get the car going. There are definitely other causes for hard starts, but if you're experiencing some of these other symptoms as well, make sure you give the fuel filter look to see if it's the problem.
Reduced Engine Power
If you're driving a car that you've been familiar with for a time now, then you should be familiar with how it feels and how it reacts on the road. This can help you diagnose a problem with your fuel filter if you're discovering that for no reason your car seems to be struggling to maintain the kind of power that you're used to. If you're finding that accelerating is difficult or going up a hill is a struggle, it's very likely that you have an issue with a clogged fuel filter.
Broken Fuel Pump
Of course there are a number of reasons that your fuel pump could break in your vehicle but a clogged fuel filter is one of those potential causes. If the filter is clogged badly enough the strain that it puts on the fuel pump can end up causing the fuel pump to burn itself out. It does make sense when you think about it because the pump is struggling to move fuel but it’s just not able to go anywhere because the filter is holding it back.
Check Engine Light
This is the most frustrating symptom of a problem in your vehicle that you're ever going to experience because it's not very helpful in diagnosing a problem. A check engine light on your dashboard could mean any one of hundreds of things has gone wrong in your vehicle. However, if you're experiencing one or more of these other symptoms then that greatly narrows the field for why the check engine light came on and could be an indicator that you're having a problem with your fuel filter.
If you want to help narrow down why a check engine light came on your dashboard you can invest in your own OBD2 scanner from a site like amazon.com. Although your mechanic probably has a more expensive and detailed version, you can get a simple OBD2 scanner for as little as $30. This will help you diagnose problems when a check engine light comes on. For instance, if there's a problem with your fuel system you may get a code P0171 to let you know that you have an issue in that area. This is much more helpful than the vague engine light by itself.
How Long Does a Fuel Filter Last?
The lifespan of a fuel filter depends on a number of factors including the age of the car you're driving, the kind of fuel you use, and how you drive the vehicle. But for a good rule of thumb you can expect at a fuel filter should last you between 20,000 miles and 40,000 miles. That should work out to a couple of years worth of driving on average. The best way to know for sure if you need a new fuel filter is to get a fuel pressure test so that your mechanic can tell if the fuel is still going through the lines at the right pressure or the filter has become clogged up. On the other hand, since a fuel filter is so inexpensive anyway if you feel like you've probably used the one in your car for as long as it's expected to last, you can simply buy a new one and replace it and still save yourself quite a bit of money.
What Does it Cost to Replace a Fuel Filter?
If you need to go into a mechanic to get your fuel filter replaced it's not going to be too expensive a job to get done. Including the cost of labor, you can likely expect a mechanic to charge you between $50 and $175 to get the job done. This is definitely going to be most greatly affected by both the make, model, and year of vehicle you drive and where you take it to get it repaired.
As you no doubt know, even routine maintenance and repairs cost more money at a dealer then they will add a neighbourhood mechanic. On top of that, the more high-end your vehicle is the more likely it's going to cost you more money to get something even as simple as a fuel filter repaired. The cost of getting this job done in a Honda Accord is going to be a little less than you're going to pay for a vehicle like a Bentley Mulsanne or a Lamborghini Diablo, for instance. Of course, if you're driving a Lamborghini Diablo, you can probably afford to pay a few extra dollars for your fuel filter anyway.
Can I Replace My Own Fuel Filter?
If you head to AutoZone you'll see that a fuel filter by itself is remarkably cheap. Some of these are actually under $4 a piece. On the high end of the scale you're only spending $20 to $30 for a fuel filter. So you can save yourself a few dollars if you replace the fuel filter in your car on your own rather than taking it to a mechanic. The process of replacing a fuel filter isn't overly complicated and if you are comfortable changing your oil filter or swapping out a dead battery under the hood then you are probably able to manage changing a fuel filter as well.
If you've never changed the fuel filter before and aren't sure of how to get the job done the internet can definitely lend you a hand in this task. There are a lot of skilled mechanics who have extremely helpful YouTube channels that can guide you through the process. A video like this one will show you step-by-step exactly what you need to do so you don't need to worry about missing any steps are doing something the wrong way. It's definitely worth it to save yourself $100 or more on a job like this for something that you can just do it a few minutes at home.
The Bottom Line
As you can see the fuel filter in your car is one of the least expensive parts of a vehicle that you'll ever have to replace. That doesn't mean it's not important, however. If your fuel filter gets too badly clogged, then you can see there are a number of potentially inconvenient and even dangerous side effects that you might have to deal with. The last thing you want is your car stalling out on you while you're driving down the highway because your engine couldn't get the right amount of fuel to continue running properly.
As inconvenient as it is to realize that your fuel filter has become too clogged to work properly you can at least take comfort in the fact that it was doing its job up until that point because it obviously managed to keep a lot of debris out of your fuel lines that's allowing your car to burn fuel more efficiently.
Being that your fuel filter is both cheap and easy to fix, there's no real reason to neglect this particular piece of maintenance for longer than you need to. If you start experiencing any symptoms, get yourself a new fuel filter and swap it in for the old one as soon as you can.