Fuel Filter Maintenance For 2009 Mercedes C350: When To Change?

If you're experiencing engine failure, it may be time to change your fuel filter. A clogged or faulty fuel filter can cause poor engine performance and, if left completely clogged, can leave you with an engine that doesn't run at all. Luckily, there are several symptoms that indicate a fuel filter is going bad, including a lit Check Engine light, rough starts, engine lag, and a misfiring engine. You may also experience shuddering when idling, your vehicle may stall, and you may not be able to start it.

Mercedes-Benz vehicles typically have two types of fuel filters: a strainer located in the fuel tank and another located in the main fuel line. The fuel filter is usually located somewhere between the tank and the engine.

It is recommended to replace your fuel filter every 100,000 miles if you want your car to perform like new.

Fuel filter replacement parts

When to Change the Fuel Filter

It is recommended to replace the fuel filter on your 2009 Mercedes C350 every 60,000 miles. However, if you are experiencing any issues with engine performance, such as poor acceleration, sputtering, or rough idling, it may be necessary to replace the fuel filter sooner.

Tools Required

• 8mm socket
• Large flathead screwdriver
• Hammer

Parts Required

• Fuel filter
• Fuel filter-sealing O-ring

Step-by-Step Guide

Figure 1: Begin by opening the fuel filler door and removing the gas cap to relieve pressure in the system.

Figure 2: Disconnect the fuel lines from the pump. Both the filter and pump are located under the rear seat, with the pump on the right side and the filter on the left. Remove the rear seat for access.

Figure 3: Disconnect the two fuel lines from the fuel pump on the right side.

Figure 4: With the rear seat removed, use an 8mm socket to remove the four bolts securing the access cover for the fuel filter. Lift the cover off, taking care to peel away the sealant gasket around the wiring connection.

Figure 5: Disconnect the two electrical connections from the filter and clean around the retaining ring and lid.

Figure 6: Remove the locking ring that holds the filter in place in the gas tank. Mercedes offers a specific tool for this, but a large flathead screwdriver and a small hammer can also be used. Gently tap the ring back off the tabs, moving continuously around the ring. There should be a witness mark on the ring to indicate when it is fully unlocked. With the ring unlocked, remove the fuel line by squeezing the tab and lifting it off the filter. A small amount of fuel will spill, so be prepared to catch and dispose of it correctly.

Figure 7: Remove the retaining ring and note the position of the filter in the tank. The large tab on the front of the filter must face towards the front of the vehicle.

Figure 8: Carefully lift the filter out of the tank, being careful not to bend or damage the left-side level detector. Remove the filter, leaving the hoses to the pump attached. The fuel pressure sensor can be transferred to the new filter by removing the retaining ring.

Where to Buy Replacement Parts

Replacement fuel filters for the Mercedes C350 can be purchased from various online retailers, such as Amazon and Pelican Parts. It is important to ensure that the replacement part is compatible with the specific year and model of your vehicle. Always refer to your owner's manual or seek advice from a qualified mechanic if you are unsure about the correct replacement parts for your car.

Fuel filter replacement tools

The following tools are required to replace the fuel filter on a 2009 Mercedes C350:

• 8mm socket
• Large flathead screwdriver
• Hammer

It is important to note that the fuel filter replacement procedure may vary depending on the specific model and VIN of your Mercedes C350. Therefore, it is recommended to have your VIN handy when ordering parts and refer to the appropriate repair manual or seek assistance from a qualified mechanic.

Additionally, it is crucial to take safety precautions when working with fuel. Always wear proper clothing, gloves, and safety glasses. Work in a well-ventilated area, preferably outdoors, and avoid using incandescent work lights or power tools. Do not smoke near the vehicle during the replacement process as fuel and fuel vapors are highly combustible.

Fuel filter replacement safety precautions

Fuel filters are a critical component of a vehicle's fuel supply system, trapping dirt, rust, and other impurities from the fuel before they can reach the engine. When replacing a fuel filter, it is important to take several safety precautions to ensure the process is completed safely and effectively. Here are some key safety measures to follow:

Wear Proper Safety Gear

When working with fuel, it is important to wear appropriate clothing, gloves, and safety glasses to protect yourself from fuel and fuel vapors. Fuel is highly combustible, so it is crucial to avoid any potential ignition sources, such as smoking or using incandescent work lights or power tools. Working outdoors or in a well-ventilated area is recommended.

Relieve Pressure in the Fuel System

Before beginning the replacement, relieve pressure in the fuel system by opening the fuel filler door and removing the gas cap. This step helps to reduce the risk of fuel spraying when the fuel lines are disconnected.

Disconnect the Fuel Lines

To replace the fuel filter, the fuel lines will need to be disconnected from the pump. Exercise caution during this step to avoid spilling fuel. Be prepared to catch and correctly dispose of any spilled fuel.

Remove the Old Fuel Filter

The fuel filter is typically located under an access cover, which can be removed using the appropriate tools. Once the cover is removed, disconnect any electrical connections and carefully lift out the old fuel filter, being mindful of any attached hoses or components.

Install the New Fuel Filter

When installing the new fuel filter, ensure that it is positioned correctly and securely fastened in place. Reattach any disconnected electrical connections and close the access cover.

Check for Leaks

After installing the new fuel filter, it is crucial to check for any fuel leaks before starting the engine. Inspect the fuel lines thoroughly and ensure that all retaining clips and mounting brackets are correctly reinstalled.

Replace O-Rings, Gaskets, and Seals

In addition to replacing the fuel filter, it is recommended to replace all O-rings, gaskets, and seals in the fuel system to maintain its integrity and prevent leaks.

Work with a Cool Engine

Always allow the engine to cool down completely before attempting any fuel filter replacement or maintenance work.

Accessible Location

When installing a new fuel filter, choose a location that is easily accessible for future maintenance or replacement. Ensure that the filter is securely mounted and will not be bumped or hit.

Use a Container for Fuel

During the replacement process, have a container ready to catch any fuel that may leak from the fuel lines or the filter itself. This will help prevent fuel from spilling onto the floor of your vehicle or boat, which can cause damage.

By following these safety precautions, you can help ensure that your fuel filter replacement is completed safely and effectively, reducing the risk of accidents or damage to your vehicle.

Fuel filter replacement steps

Safety Precautions:

• Wear proper clothing, gloves, and safety glasses when working with fuel.
• Work in a well-ventilated area, preferably outdoors.
• Do not smoke, and avoid using incandescent work lights or power tools as fuel and fuel vapors are highly combustible.

Tools and Parts Required:

• 8mm socket
• Large flathead screwdriver
• Hammer
• Fuel filter
• Fuel filter-sealing O-ring

Step-by-Step Guide:

Figure 1:

Open the fuel filler door and remove the gas cap to relieve pressure in the system.

Figure 2:

Disconnect the fuel lines from the pump. Both the filter and pump are located under the rear seat, with the pump on the right and the filter on the left. Remove the rear seat for access.

Figure 3:

Disconnect the two fuel lines from the fuel pump.

Figure 4:

With the rear seat removed, use the 8mm socket to remove the four bolts securing the access cover for the fuel filter. Lift the cover, peeling away the sealant gasket around the wiring connection.

Figure 5:

Disconnect the two electrical connections from the fuel filter. Clean around the retaining ring and lid.

Figure 6:

Remove the locking ring holding the filter in the gas tank. Mercedes offers a specific tool for this, but a large flathead screwdriver and small hammer can be used carefully. Tap evenly around the retaining ring to unlock it, then remove the fuel line by squeezing the tab and lifting it off the filter. Some fuel will spill, so be prepared to catch and dispose of it properly.

Figure 7:

Note the position of the filter in the tank. The large tab on the front of the filter must face towards the front of the vehicle.

Figure 8:

Carefully lift the filter out of the tank, being cautious not to bend or damage the left-side level detector. Remove the filter with the hoses to the pump still attached. Transfer the fuel pressure sensor to the new filter by removing the retaining ring.

Installation:

Installation is the reverse of the removal process. Ensure the lid is positioned and sealed correctly.

Fuel filter replacement symptoms

Fuel filters in Mercedes-Benz cars are important to ensure that the fuel entering the engine is free of pollutants and other particles that can lead to engine failure or performance issues. There are two types of fuel filters in most Mercedes-Benz vehicles: a strainer located in the fuel tank and another located in the main fuel line.

• Check Engine Light Illuminated: If the Check Engine light on your dashboard is lit, it could be a sign of a clogged fuel filter.
• Difficulty Starting the Car: If you're experiencing difficulty starting your car, it might be due to a clogged fuel filter that is impeding the fuel flow to the engine.
• Engine Misfiring: A clogged fuel filter can cause the engine to misfire, as it affects the fuel flow and reduces the volume of fuel reaching the engine.
• Poor Engine Performance: A faulty fuel filter can lead to poor engine performance, including reduced acceleration, sputtering, and rough idle.
• Shuddering or Stalling: If your car shudders when idling or stalls frequently, it could be a sign that the fuel filter needs replacement.
• Inability to Start the Engine: In some cases, a completely clogged fuel filter can result in an engine that doesn't run at all.

It is recommended to replace the fuel filter every 100,000 miles or when you notice any of the above symptoms. Replacing the fuel filter can help improve engine performance and prevent engine issues caused by contaminated fuel.

Additionally, it is important to maintain your vehicle by following the suggested maintenance plan in your owner's manual and using the correct type of gasoline. Regular fuel system checks by a professional can also help identify and prevent issues with the fuel filter and other components.

Frequently asked questions