Changing Fuel Oil Filters: Step-By-Step Guide For Beginners

Changing the fuel oil filter is a simple task that can be done at home with the right tools and safety precautions. It is important to change the filter regularly, as this helps improve furnace reliability, maximize efficiency, extend the lifespan of the furnace, and save money. The process involves turning off the power and oil supply, removing the filter base, cleaning the filter canister, adding a new filter, bleeding air from the filter, and turning the power and oil supply back on. The frequency of changing the filter depends on various factors, but it is generally recommended to be done at least once or twice a year.

Turn off electricity and oil supply

Before you begin changing the fuel oil filter, it is important to take the necessary safety precautions. The first step is to turn off the electricity and oil supply to your heating or cooling equipment. This is a crucial safety measure to reduce the risk of electric shock and prevent oil leaks.

Locate the shut-off valve on the oil supply line above the filter and turn it off. Even after turning off the oil supply, there may still be some residual oil left in the line and the filter. To catch any oil drips or spills during the filter change, place a pan or bucket underneath the filter to avoid contamination in your home.

It is important to note that different heating systems have different setups. For example, a two-line system may have valves on both the feed and return lines, which should be closed before changing the filter. In contrast, a single-line system typically has a shut-off valve on the oil supply line. Consult a professional or refer to the specific instructions for your heating system if you are unsure about the exact location of the shut-off valves.

Once you have turned off the electricity and oil supply and taken the necessary precautions to catch any oil spills, you can proceed to the next steps of changing the fuel oil filter. Remember to exercise caution and follow the recommended safety guidelines throughout the process.

Remove filter base

Removing the filter base is a crucial step in changing the fuel oil filter. Here is a detailed guide on how to do it:

Locate the Bolt or Supply Line: The first step is to identify how the filter base is attached to the unit. It is usually secured with a bolt or by being screwed into the supply line. If your unit has a bolt, you will need to loosen it, while for a supply line, you will need to unscrew the base.

Prepare a Catch Pan: Before removing the filter base, place a catch pan or bucket underneath the filter to catch any oil drips or spills. This is an important safety precaution to avoid oil contamination in your workspace or on the floor.

Loosen the Bolt or Supply Line: Using the appropriate tool, carefully loosen the bolt that holds the filter base in place. If your unit has no central bolt, you will need to unscrew the canister base from the top of the supply line. Be cautious not to let the base fall and spill its contents.

Remove the Filter Base: Once the bolt is loosened or the supply line is unscrewed, carefully lift and remove the filter base. This will grant you access to the old filter cartridge, which can be disposed of or cleaned, depending on the type of filter your unit uses.

Dispose or Clean the Old Filter: If your unit uses disposable filters, carefully remove the old filter cartridge, along with any used gaskets, and set them aside for proper disposal. If your unit has a permanent filter, follow the manufacturer's instructions for cleaning and maintenance.

Remember, when performing these steps, it is important to wear protective gloves and have a designated space to place small parts like washers and O-rings, so they are not lost during the process.

Clean filter canister base

To clean the filter canister base, there may be a buildup of oil and sludge in the canister base and top. Clean this out with a soft toothbrush or a cloth. If it is very dirty, you can also soak the pieces in kerosene for a minute or two and then go to work on them with a soft brush. Follow the same cleaning process if you have a unit with a permanent filter.

The filter canister should be cleaned after removing the old filter and before installing a new one. This is to ensure that the new filter is not installed in a dirty canister, which would defeat its purpose.

If your unit has a pump strainer, it is also a good idea to clean it when changing the oil filter so that your whole unit will run cleanly and clearly. To do this, lift the cover over the strainer and pull out the wire mesh strainer. Wipe it down with a cloth or soak it in kerosene for a minute or two to loosen any buildup. Then, scrub it with a soft-bristled brush and wipe it off well. Make sure to check the strainer at the same time to ensure that there is no damage to the piece that would warrant a total replacement.

Add new filter

Now that you have removed the old filter, cleaned the filter canister, and checked for water seepage, it's time to install a new filter.

The new filter will usually be a cartridge that fits into the canister base. Place the cartridge into the base, and screw the base directly into the top piece, or use a bolt to tighten it into place.

Make sure that the O-ring that seals the connection between the top and base is secure. If your cartridge package came with new gaskets, swap these in for the existing ones. If there was no O-ring included, check the quality of this part before screwing it back in. If the old seal looks cracked, brittle, or otherwise damaged, be sure to purchase and install a new one before screwing the filter back on.

Now that the new filter is in place, you can reassemble the heating oil filter canister. Slide the canister base under the canister lid and into the correct position, keeping the filter cartridge steady and centred as you do so.

Once the two pieces of the oil filter canister are back together, replace the bolt at the top of the canister. Tighten it securely, but be careful not to apply too much pressure, as this can strip the threads. If the canister does not have a bolt, make sure the base is screwed in tightly.

Bleed air from the filter

Bleeding air from the filter is a crucial step in changing the fuel oil filter. Here is a detailed, step-by-step guide to help you with this process:

Prepare the Fuel System for Bleeding

Before you begin, ensure that you have turned off the engine and removed the ignition key from the cylinder. Locate the fuel filter and determine whether it has a built-in bleeder screw. If your fuel filter has a bleeder screw, position a clean rag or towel beneath it to catch any fuel spills. This will also help you observe the flow of fuel and air mixture during the bleeding process.

Loosen the Bleeder Screw

Using a wrench or bleeder screw key, slowly loosen the bleeder screw in a counterclockwise direction. This will release the trapped air and fuel mixture. Allow the bleeding to continue until you see only fuel flowing from the screw without any air bubbles. Once done, tighten the bleeder screw securely.

If your fuel filter does not have a bleeder screw, you may need to loosen the filter slightly to allow air to escape. Be cautious, as you don't want to fully remove the screw. Just loosening it should be enough to release the air. Make sure not to strip the threads on the small screw.

Bleed the Fuel System at the Fuel Injectors

If your fuel filter lacks a bleeder screw, or if you suspect that air remains in the system, you may need to bleed the fuel system at the fuel injectors. Locate the engine's fuel injectors, usually connected to the fuel lines. Use a wrench or socket set to loosen the fuel line connection.

Crank the Engine and Observe the Fuel Flow

Crank the engine for a few seconds to allow any remaining air to escape. Be cautious of fuel spills during this step. Tighten the fuel line connection when you observe a steady fuel flow without any air bubbles. Repeat this process for each cylinder and fuel injector, starting with the one closest to the fuel pump and working your way to the farthest.

Check for Remaining Air

After bleeding the fuel system, try to start the engine. If the engine starts, let it idle for a few minutes while checking for signs of rough idle or reduced power. Inspect the fuel system components for any fuel leaks or damage. If the engine doesn't start or there is still air in the system, repeat the bleeding process at the fuel filter or fuel injectors.

Clean-Up and Maintenance

After successfully removing the air from the fuel system, properly dispose of any spilled fuel, and clean the area. Return your tools to their proper place, and ensure ongoing maintenance by regularly checking for leaks and proper fuel delivery.

Frequently asked questions