Mercedes-Benz C-Class fuel filter should be replaced approximately every 50,000 kilometers. Main functions of the fuel filter: Filter impurities in gasoline, remove impurities and moisture from the fuel, improve the cleanliness of gasoline, and prevent impurities from entering the fuel system and affecting the injection system. As long as the fuel added is clean, the filter can be used for a long time without issues. Classification of fuel filters: Fuel filters come in two types: built-in and external. The external filter has an iron shell with filter paper inside to filter impurities. The external filter has a relatively short service life and should be replaced around 50,000 kilometers. The built-in filter (used in most Mercedes-Benz vehicles today) is more difficult to remove, so it is designed with a large-capacity, long-lasting filter material. The built-in filter is recommended to be replaced around 100,000 kilometers. Working principles of built-in and external filters: The working principle of the built-in filter is completely different from that of the external filter. The external filter is located after the fuel pump, where the fuel output by the pump passes through the filter paper inside the external filter under pressure. The built-in filter is placed at the input end of the fuel pump, where the fuel is filtered by the filter material inside the filter screen before entering the fuel pump. This filter material has a large volume and high filtration capacity, resulting in a relatively longer service life. Symptoms of a clogged fuel filter: Weak acceleration and noticeable power loss when the car is fully loaded. Severe engine vibration at idle. Difficulty starting or inability to start the car.
