MAINTENANCE, LUBRICATION AND SERVICE
FUEL SYSTEM
• Fuel stored for a long time may
oxidize and form solids, causing
ltering problems.
• Keep the area around the ll cap
clean.
Generally, fuel contamination occurs as
the result of improper fuel handling. The
most common types of contamination
are water, dirt and microbial growth
(black slime). The formation of varnishes
and gums resulting from poor fuel
stability or long storage (stale fuel) also
affects fuel quality. The best treatment
for contamination is prevention by
maintaining a clean storage system and
choosing a reputable fuel supplier.
Fuel Filters
A primary fuel lter can be located on
the engine or remote mounted on the
frame rail. This lter consists of a lter
cartridge, a water separation bowl and
may have a fuel heater built in.
The secondary fuel lter is located on
the cold side of the engine, below the
engine electronic control unit (EECU).
The lter is a spin-on lter.
Mack MP engines utilize a spin-on
primary and secondary fuel lter. Both
lters are located on the cold side of the
engine
1 Secondary Fuel Filter
2 Primary Fuel Filter
The primary fuel lter on Mack MP
engines incorporates a plastic water
separator bowl. Additionally, the plastic
bowl includes a water-in-fuel sensor. A
warning lamp on the instrument panel
illuminates when water is detected in the
fuel.
NOTE
There are optional fuel lter systems (such
as Davco, Conmet, etc.) available for
Mack MP engines. These fuel lter
systems use a single remote-mounted
lter, eliminating the spin-on primary and
secondary lters. For service information
concerning these lters, refer to the
specic fuel lter manufacturers service
literature.
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