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Fuel Filter Basics: What It Does and When to Replace It

Fuel Filter Basics: What It Does and When to Replace It

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Diesel engines used by heavy duty trucks and commercial vehicles today are far from the engines they were equipped with in the past. They are now more energy-dense, fuel-efficient,  tougher, and cleaner. This is to ensure they work more efficiently, last longer, consume less fuel, and adhere to stricter emissions regulations. 

Fleet managers, heavy duty truck owners, and commercial vehicle operators, however, must understand that a high-efficiency fuel filtration system is equally important to ensure these engines perform at their best and keep the vehicles on the road longer. This serves as their vehicles’ front line of defense against unplanned downtime and costly operational expenses. That is why to ensure your heavy-duty engines will last as long as your vehicles, you must equip them with high-performance fuel filters

Fuel Filter Function Explained

The fuel filter is a crucial part of the fuel system, which stores and supplies fuel to the combustion chamber, where it can be mixed with air, vaporized, and burned to produce the energy needed to start the engine. Its main function is to screen dirt, rust particles, and other pollutants from the fuel and prevent them from entering the engine and cause damage. If any of these contaminants enter the engine, they can cause unnecessary wear and tear on the different engine components and reduce the amount of flowing fuel, resulting in poor overall engine performance.   

But just like the other types of filters, the fuel filter should be replaced at regular intervals, as recommended by your truck manufacturer. This is to ensure your engine works at the optimum level at all times. Fuel filters usually require a change every 10,000 to 15,000 miles. However, as your vehicle ages, the fuel filter can get clogged sooner than expected and need to be replaced more frequently. 

Signs Your Truck Needs a New Fuel Filter

While you can always refer to your vehicle’s manual for the recommended fuel filter change interval, it still pays to know how to tell when you have a failing fuel filter. Listed below are seven telltale signs your truck needs a new fuel filter. 

Trouble starting or no start at all

There are so many reasons why your engine has trouble starting or does not start at all. These include a faulty spark plug, a problematic starter, a damaged fuel pump, or a dead battery. But, if your engine cannot draw fuel while the fuel pump is fine, then a clogged fuel filter is the most likely culprit. To confirm this, you may check the fuel gauge and the fuel in the tank.

Check engine light illuminates

A check engine light illuminating indicates issues with your truck. Although a bad fuel filter does not trigger the check engine light to illuminate, the problems resulting from it do, such as problems in fuel delivery, mass air flow sensor, and engine. To avoid any of these, you must observe a regular maintenance check of your truck components—the fuel filter included. 

Engine misfiring randomly

When the engine misfires, it means an error occurred in one of the combustion chambers. While a partially clogged filter is not the likely culprit, a fully clogged filter can be one of the factors. So, to confirm this, you must first eliminate all the other factors, such as ignition system issues, transmission problems, or mechanical parts failure. 

Shaky engine idling

If your truck begins to shake when you are idling or driving at low speeds, chances are there’s not enough fuel being delivered to the engine. And what could be the most likely reason for this? It’s none other than a clogged fuel filter. It prevents the engine from getting an even continuous supply of fuel, so it starts to shake. Avoid this by regularly checking the filter and replacing it when necessary.

A significant change in vehicle’s power

If you start to notice a sudden drop in engine performance—when hauling a heavy load, accelerating, or heading up a steep incline—it could be that your truck is having fuel distribution issues. When the vehicle is under too much stress, it needs more fuel to produce more power that could resist gravity. This will not be possible if your fuel filter is clogged, so you’d better replace it if this symptom matches up with the rest on the list.  

Poor gas mileage

You might think that when there’s less fuel passing through to the combustion system, it will improve fuel efficiency. Well, that is not the case because what the engine does is it requires the fuel pump to supply more fuel than necessary to produce the power it needs to run. As a result, your truck starts consuming much more fuel than usual, leading to poor fuel economy. 

A damaged fuel pump

When you’ve got a clogged fuel filter, not only your engine is deprived of the right amount of fuel it needs during combustion but also your fuel pump is required to work harder than usual. And if this is left unresolved for too long, the fuel pump will get completely damaged. So, once you notice any of the signs above, be sure to check the fuel filter at once before the fuel pump and other parts of the engine become compromised. 

Replacing a clogged or bad fuel filter as soon as you confirm the issue is highly recommended to avoid dealing with more serious engine issues later on. Getting a brand-new filter is very easy anyway, especially when you do your shopping right here at FinditParts

FinditParts is the leading supplier of heavy duty truck and trailer parts online. We have over 10 million parts cataloged on our easy-to-navigate website, including the replacement fuel filters you need. We offer different types of filters—from engine air filters and oil filters to fuel filters—from some of the most popular brands like Wix Filters, Fleetguard, and Racor Filters. Check out our catalog to find the exact match fuel filter for your truck today.