My Mercedes Benz C class fuel pump stopped working

Thursday September 6 2018


Hello Paul, I follow your articles and they have helped me to maintain my Mercedes Benz C class. Recently, the fuel pump stopped working, we replaced it with a new one. However, the mechanic recently told me that the new pump has a leakage. What is causing this? Mukisa.

Hello Mukisa, failure of the fuel pumps or leakages such as this are commonly caused by blocked fuel filters overdue for replacement. The fuel system of your Mercedes, like all other vehicles, relies on flow pressure to deliver ample fuel to run the engine at optimum performance. The main causes of a drop in fuel pressure include failure of the fuel pump, blockage of the fuel filter, leaking fuel lines and malfunctioning or blocked fuel injectors.

In this case, the nearest intervening variable to the fuel pump is the fuel filter. If it is blocked, back pressure will force the new pump to leak petrol. The fuel filter should have been replaced at the same time with the fuel pump as it may have caused failure of the old pump in the first place.

Replacement of long life fuel filters periodically, after 100,000 kilometres, is essential to avoid damage of the fuel pump and other fuel system components such as fuel injectors.
Also, avoid buying fuel from road side fuel kiosks whose fuel tanks maybe dirty with gunk and corrosion or dispensing pump filters ineffective.