Replacing Davco Fuel Filter: Step-By-Step Guide For Beginners

Davco fuel filters are used in diesel-powered engines and are known for their patented Seeing is Believing® technology. The filters are designed to provide maximum uptime by ensuring optimal fuel/water separation performance. Davco recommends using only EleMax filters due to their high efficiency and high capacity filtration. The fuel level in a Davco filter can vary, and it is important to read the filter while the engine is running to determine if a change is necessary. Some people choose to change their filters once a month or with every oil change, while others wait until the filter is halfway full or until they notice a drop in power. There are detailed instructions available online for how to change a Davco fuel filter, and it is a task that can be performed by truck drivers themselves or by professionals for a small fee.

How to know when to change the filter

Knowing when to change your Davco fuel filter is important to ensure your engine is protected and maintained. Davco fuel filters are designed for diesel-powered engines and feature a patented clear cover top that allows you to monitor the filter's condition. Here are some detailed instructions on how to know when to change your Davco fuel filter:

• Check the Fuel Level: The clear cover top on Davco fuel filters allows you to visually inspect the fuel level. If the fuel level reaches the "change line," it indicates that the filter needs to be replaced. It is important to check the fuel level while the engine is running, as the level may vary when the engine is off.
• Monitor Engine Performance: Keep an eye on your engine's performance. If you notice a sudden drop in power or experience surging while driving, it could be a sign that your fuel filter needs attention. A restricted fuel flow can cause a decrease in engine performance.
• Check for Warning Lights: Some vehicles are equipped with dashboard warning lights that indicate when the fuel filter needs to be changed. Keep an eye on these lights and take appropriate action when they illuminate. However, it is important to note that a fuel filter issue may not always trigger a warning light.
• Regular Maintenance: While it is important to monitor the fuel filter's condition, preventive maintenance is also key. Consider changing your fuel filter regularly, such as during each oil change or at specific mileage intervals recommended by the manufacturer. This can help prevent potential issues caused by dirty fuel or fuel contaminants.
• Fuel Quality and Contaminants: Be mindful of the quality of fuel you are using. If you notice issues with fuel quality or the presence of contaminants, it may be necessary to change your fuel filter more frequently. Bio-diesel, for example, can lead to increased filter clogging due to the cleaning nature of the fuel.

By following these guidelines and staying vigilant, you can effectively determine when it is time to change your Davco fuel filter. Remember to refer to the owner's manual or seek advice from a qualified mechanic if you have any questions or concerns.

How to prime the fuel system

To prime the fuel system of a Davco fuel filter, follow these steps:

Firstly, locate the fuel filter and ensure you have the necessary tools and equipment to perform the task. This includes a new fuel filter, a drain pan, gloves, and safety goggles. Before beginning any work, ensure the engine is turned off and allow it to cool down if necessary.

Next, identify the fuel filter's vent cap port, which is located on the top of the clear cover. Remove the vent cap carefully and set it aside. Using a clean funnel, slowly and carefully pour fuel into the vent cap port until it reaches the top of the filter. It is important to take your time during this step to avoid any spills or overfilling.

Once the filter is filled with fuel, carefully replace the vent cap securely. Now, locate the fuel pump and activate the priming feature, following the specific instructions for your vehicle's model. This process will vary depending on the make and model of your vehicle, so refer to the owner's manual or seek guidance from a professional if you are unsure.

After priming the fuel pump, start the engine and let it run for a few minutes. Observe the fuel filter and ensure that the fuel level remains stable and does not drop significantly. If the fuel level drops, repeat the priming process and top up the fuel as needed.

Finally, once the fuel system is primed and stable, you can proceed with any other necessary maintenance or repairs. Remember to always exercise caution when working with fuel and refer to a professional mechanic if you have any doubts or concerns.

How to diagnose fuel problems

Diagnosing fuel problems in a Davco fuel system is straightforward, thanks to the company's Seeing is Believing® technology. This patented clear cover top allows users to diagnose fuel problems simply by looking at the fuel inside the clear cover.

For example, if you notice air bubbles in your fuel system, this could indicate an air leak in the fuel line between the fuel tank and the lift pump. If the fuel level is low, this could indicate a leak in the fuel system, or that the filter is clogged with dirt, debris, or other impurities. If the fuel level is high, this could mean that the filter is not compatible with your vehicle and cannot handle the fuel's flow rate.

Davco also provides literature on how to distinguish air from vapour bubbles in a diesel fuel system. This can be downloaded from their website.

Other fuel problems may be caused by issues with the water separator or the filter head. For example, if there is water in the fuel, it can cause corrosion and reduced engine performance. A water separator uses centrifugal force to separate the water from the fuel, so it is important to regularly check and service it to avoid damage to the engine. The filter head regulates the fuel pressure and directs the fuel flow from the tank to the engine. If the fuel filter isn't getting enough fuel, the filter head may be damaged, clogged, or leaking, and will need to be replaced.

How to distinguish air from vapour bubbles

There are two types of bubbles that may be visible at the fuel pump inlet of a diesel fuel system: air bubbles and vapour bubbles.

Air bubbles are caused by any air leak on the vacuum (suction) side of the fuel system, from the fuel tank pick-up to the lift pump. If there is an air leak in the fuel system, air bubbles will be present in the clear cover of the Fuel Processor. If there are no bubbles present in the Fuel Processor cover and the engine continues to run rough, there may be an air leak between the Fuel Processor outlet port and lift pump inlet. This type of air bubble can be seen if a sight tube is installed at the lift pump inlet.

Vapour bubbles develop in the Fuel Processor because the pressure inside the Fuel Processor is lower than the atmospheric pressure in the fuel tank. The lower pressure draws the entrained air/vapour out of the fuel, and these bubbles will be visible as the fuel exits the Fuel Processor. As the fuel enters the lift pump, it is pressurised and the bubbles are compressed back into the fuel. There will be no bubbles on the fuel return side of the system.

An easy way to determine the difference between vapour and air bubbles is by temporarily removing the filter element from the Fuel Pro. Fill the cover with clean diesel fuel, replace the vent cap and re-run the outlet fitting sight glass test. If there are no bubbles present in the sight glass, they were vapour bubbles. If bubbles are still present, they are air bubbles.

How to read the filter

Reading the fuel filter level on a Davco filter is important to know when to change it. The filter should be read while the truck is running, not while it is shut off. The fuel level in the Davco filter can vary, so it is important to check it regularly. To check the fuel level, look through the Davco patented Clear Cover to see the fuel level. The cover also allows you to diagnose fuel problems, such as fuel temperature issues, air leaks, and loss of prime.

The fuel level can be affected by various factors, such as the temperature of the engine and how long it has been shut off. For example, one user found that after the engine was hot but had been shut off for a few minutes, the fuel level was at the "change line". However, when they started the engine and idled for a few minutes, the level stayed at the bottom. So, it is important to check the fuel level regularly and under different conditions to get an accurate reading.

Another way to know when to change the fuel filter is to notice a drop in power due to restricted fuel flow. However, this may not be noticeable until the filter is already significantly clogged. Therefore, it is important to regularly check the fuel level and not rely solely on power or mileage intervals.

Davco recommends using only EleMax filters due to their easy-to-see filter change level, among other features. The EleMax filter has a clear cover top that allows you to see when the filter is ready to be changed, reducing waste by using the full capacity of the filter. This can help extend filter change intervals based on useful filter life instead of mileage or a calendar date.

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