Engine 321 Avoid fire, naked flames, smoking and creat- ing sparks under all circumstances. Switch off the ignition and auxiliary heating before car- rying out work to the fuel system. Always wear protective gloves. B Inspection window C Drain plug X Place a collector under drain plug C . X Open drain plug C . To do so, turn the drain plug to the left. H Environmental note Dispose of the water-fuel mixture in an envi- ronmentally responsible manner. X Press hand pump ? several times in suc- cession and collect the fuel/water mixture. X Close drain plug C . To do so, screw the drain plug tightly to the right.
H Environmental note Dispose of used filter elements, seals and fuel residue in accordance with relevant local reg- ulations. X Bleed the fuel system ( Y page 322). X Check the fuel system for leaks. Replacing the fuel prefilter Draining the fuel prefilter Breakdown assistance Drain fuel prefilter : regularly. X Remove bolts ; on cover plate = . X Remove cover plate = . Example : Filter head ; Hand pump = Bleed screw ? Shutoff valve A Filter element B Sealing ring C Sealing ring D Water separator E Drain plug Example ? Hand pump A Shutoff valve X Place a collector under drain plug E . X Open drain plug E and bleed screw = . Collect the draining water-fuel mixture. Z