How Often Should You Change The Fuel Filter On A W203?

The Mercedes-Benz W203 is a C-Class car model that was manufactured between 2001 and 2007. It is recommended that the fuel filter of a W203 is changed every 30,000 miles. This can be done at a dealership or by oneself. The process of changing the fuel filter involves relieving the fuel pressure, removing the underbody tray, taking off the fuel filter, and installing a new one. This process can take around 30 minutes to an hour.

Locating the fuel filter

The fuel filter on the Mercedes-Benz W203 (2001-2007) is located on the underside of the car, behind the rear left side seat. To access it, you will need to safely lift and support your car.

Once the car is safely supported, you will need to remove the underbody tray to give you enough room to work on the filter.

To begin, remove the T25 Torx screw holding the filter in place. Move the filter out of its holding bracket to give you more room to work.

The fuel filter will be located next to the driver's rear tire.

Tools required

The following tools are required to change the fuel filter on a W203:

• A new fuel filter
• New hose clamps
• Socket wrench with 8mm and 10mm sockets
• Torx T-20 screwdriver
• Jack and ramps
• A trash can lid to catch any spilled gas
• A pair of vice-grip pliers
• A whole bunch of rags
• Latex gloves

Additional tools

In addition to the above tools, you may also need the following:

• Hose clamp tool
• Cutters
• Safety glasses

Relieving fuel pressure

To relieve fuel pressure on a W203, you must first locate the fuel pressure relief valve. This is found between the airbox and the engine head, right next to the oil filler cap. Pop off the spark plug cover to find it.

Before you push down on the pin in the valve, place a whole bunch of rags around the valve to catch the escaping gasoline. It is also recommended to wear latex gloves. Then, push down on the pin in the valve (like a bicycle tire valve) to let the gas/pressure escape. Once this is done, you can put everything in the engine compartment back together again.

Removing the underbody tray

To remove the underbody tray of your W203, you will need to raise the car on the driver's side. You can use a jack and a couple of ramps for this. Make sure you have raised the car high enough at each corner to slide the ramp underneath.

The next step is to remove the driver's side belly pan or underbody tray. This is held in place with 8-10mm fasteners and 1x 8mm screw near the front of the car. First, remove the 8mm screw. Then, slide the belly pan towards the rear of the car and pull it away from the studs for final removal.

Now, you will need to relieve the fuel pressure. On the m271, the fuel pressure relief valve is located between the airbox and the engine head, next to the oil filler cap. Open the spark plug cover to find it. Place a bunch of rags around the valve to catch the escaping gasoline and be sure to wear latex gloves. Then, push down on the pin in the valve to release the gas and pressure. Once this is done, you can put everything in the engine compartment back together.

Alternatively, you can relieve the fuel pressure by removing the gas cap.

Now, you are ready to access the fuel filter, which is located next to the driver's rear tire.

Installing the new filter

Now that you've relieved the fuel pressure, raised the car, and removed the belly pan, it's time to install the new filter.

First, locate the fuel filter next to the driver's rear tire. Unmount the filter by unscrewing the strap holding it in place with a Torx T-20 screwdriver. The top of the strap can be removed by sliding it upwards.

Once the filter is loose, remove the four hose clamps and pull the hoses off. There will be gasoline pouring out of the filter and tank, so be sure to have a trash can lid on the ground to catch it. Clamp off the hose coming from the gas tank.

Next, put new hose clamps on the hoses and install the new filter, ensuring the hoses are connected to the correct ports. Tighten the hose clamps.

With everything in place, turn on the ignition and check for leaks. If there are no leaks, turn off the ignition and put the belly pan back on.

And that's it! You've successfully replaced your fuel filter.

Frequently asked questions