A drainable water separator with a warning indicator that it has quite a bit of water accumulated is really good. Water has been compared with processing sandpaper through the tight tollerance of element pistons and cylinders in the injection pump. Damages injectors as well.

This item will help maximize the usable life of the pump. It is also strange that mercedes never incorporated one. Most diesel engines did when these cars where new. Even the much cheaper volkswagon had a good water control system.