A car's fuel filter removes dirt and rust particles from the fuel supply. All filters can eventually become clogged, even in automobiles which claim to have a lifetime filter. There is no standard rule across all cars as to when a filter should be replaced.A good test is to remove the filter and blow through it. If your breath doesn't flow right through, you should replace the filter.
Locate the fuel filter. In the 2003 Volkswagon Jetta 1.8 Turbo the filter is on the passenger side of the car, front side of the rear wheel, near the gas tank. The filter itself is a small, round drum held in place by a bracket, two hoses and a black strap.
Remove the bracket that holds the filter in place with a 7-mm socket (or a screwdriver if it doesn't strip the screw). If necessary, spray some lubricant on the screw and let it soak for a few minutes.
Remove the front hose. Press the small button at the edge of the front hose clip. Keep the filter titled back to minimize the drip of fuel. The buttons can be easier to find if the car is jacked up and secured on stands. One tip is to hold the button down and use a screwdriver to wedge the hose away from the filter.
Remove the rear hose. Again, press the small button and be careful not to damage the clip or hose.
Remove the filter; the black strap will detach with it.
Attach the new fuel filter to the car. Make sure that the arrow on the filter points toward the front of the car. First attach the rear clip, then the front. Secure the filter in the bracket.
Test the new filter by starting the car. It may stall a couple of times before starting.
Check for leaks.
