How to replace the diesel fuel filter on a Mercedes E-Class W212

In this video, we will see how to replace the diesel filter on a Mercedes E-Class W212 (in this case, it is a 2.1 OM651 engine). It is advisable to have a strap wrench of the right size to unscrew the housing, although sometimes, by using a rag to increase grip, it can be done without.

We will also need a bowl to drain the diesel from the filter, located under the passenger side, protected by a small plastic cover: we will need to lift the car with a jack and support it with stands. Once the screws of the cover are removed, we see the filter which can be metallic or black plastic (depending on the production year) with two diesel pipes and an electrical connector, which we will disconnect: position the container, unscrew the cap, remove the cartridge and the o-ring.

Clean the inside of the housing from dirt and residue, insert the new gasket, lubricating it with new diesel. Fill the filter with diesel before inserting it: this greatly reduces the risk of "air in the system" and facilitates starting.

Insert the cartridge into the housing, screw on the cap and reconnect the connector. Reassemble the plastic cover and lower the car. Do not start the engine immediately: turn on the ignition and wait, repeating this cycle a few times.

This way, the fuel pump will activate, pushing fuel into the new filter and expelling any remaining air.