How to Change the Fuel Filter in a Mercedes

1. Open the hood and locate the black plastic engine cover. Grasp the edges of the cover and pull it straight up to release the holding clips, then toward the front of the vehicle to release it completely. Locate the air-intake tubes at the front of the engine that connect to the air-filter housing. Pull each tube toward the front of the vehicle to release them from the housing. Grasp the air-filter housing and pull it straight up to release the holding clips.
2. Locate the fuel-pressure release valve located at the top of the engine on the passenger side. Unscrew the plastic cap from the valve and set it aside. Place rags under and around the valve to soak up fuel. Push in on the center of the valve with a flat-blade screwdriver to release the fuel pressure. Continue pressing and releasing the valve four or five times until the fuel pressure has been released. Replace the plastic cap on the valve. Replace the air-filter housing and engine cover by reversing the order of the procedures in Step 1. Close the hood.
3. Chock the front wheels. Raise the rear of the car with a floor jack and place a jack stand under each rear frame rail. Lower the jack. Remove the retaining nuts on the plastic underbody cover on the driver's rear side of the car with a socket and ratchet. Lower the cover and place it aside.
4. Locate the fuel filter after removing the cover. Remove the fuel-filter retaining strap with a torx screwdriver. Remove the fuel lines from the filter by loosening the hose clamps with a Phillips or flat-blade screwdriver, depending on model, and then pulling the hoses from the ends of the filter. Catch any fuel coming out of the lines with rags or a small plastic container.
5. Lower the filter from the mounting bracket and discard it. Push a new filter into its place, making sure the flow arrow on the filter is pointing toward the rear of the car. Push the fuel lines back into place and tighten the hose clamps. Tighten the retaining strap on the filter with a torx screwdriver.
6. Replace the underbody cover and tighten the retaining nuts with a socket and ratchet. Raise the rear of the car with a floor jack and remove the jack stands from under the frame rails. Lower the floor jack and remove the wheel chocks.