Fuel Filter
Function
The fuel filter should protect the fuel injection systems (particularly for the diesel engine) against wear and blockage. They are relatively plain. Therefore, and because of possible heat strains they eke out their
existence mostly under the vehicle floor far away from the engine. Unfortunately, it is therefore sometimes not considered by the mechanic and might simply be overlooked. Because it features a huge capacity for dirt,
this misbehaviour most often does not have an immediate effect. Maybe only the second or third car owner will be troubled.
How it works
A lint sieve is inserted in front of the real filter paper in the fuel filter. To prevent the penetration of lint into the fuel injection system, the flow direction of the fuel is marked on the filter and should absolutely be regarded.
If used filters were inserted back to front, the whole dirt filtered out earlier could flow into the fuel injection system. To prevent a formation of dirty particles, the pipe ends should be protected during the storage with
plastic caps. Fuel filters are arranged with petrol engines mostly on the pressure side of the fuel pump. On the suction side in the large filter space the depression could cause vapour bubbles which could lead to
disturbances (e.g., hot start problems). Therefore, the fuel pipes must also not be installed in proximity of hot components (e.g., engine, catalytic converter).
