Troubleshooting - Mann Filter PreLine Series Installation And Maintenance Manual

PreLine
 Lightly lubricate the seal on the new
filter with a few drops of oil.
 Screw the filter by hand on the filter
head (not on the bowl) until the seal
makes contact.
 Turn further by hand until the filter is
firmly fixed (approx. 3/4 revolution).
 Open the bleed plug (Pos. 1, Fig. 6).
 Operate the hand pump (Pos.2, Fig. 6)
to draw fuel.
 Continue to pump until no more air
escapes from the bleed plug.
 Screw the bleed plug shut
(Ma = 6 ±1 Nm).
In the case of versions without a
hand pump, vent the system
according to the vehicle
manufacturer's instructions.
 Start the engine.
 Check the sealing quality.

5.5. Troubleshooting

Fault
Deficient engine power
No flow through after assembling the
PreLine filter system (no diesel fuel in
the water tank)
Air in the fuel system
(foam formation by fuel
pump)
MANN-FILTER
Possible cause
Filter capacity exhausted
Filter inlet/outlet
connected
Leaks in the hose connections
or seals
Drain plug open
transfer Leaks in the hose connections
or seals
Fig. 6 Bleeding
Bleed the filter, too, after working on
the fuel line!
Solution
Change the filter
incorrectly
Connect the filter inlet/outlet correctly for the
function (refer to Ch. 4.2)
Check the sealed points
Close the drain plug (refer to Fig. 3), bleed
the system as described in Chapter 5.4
Clear up any leaks, bleed the system as
described in Ch. 5.4
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