of the packing (fig. 5-15). Beside the part number,
but consult your specific engine MIMs before
the manufacturers cure date is one of the most im-
making adjustments.
After any adjustments, you must recheck the
portant items listed on the package. Refer to NAV-
pressure with a direct reading gauge at the
SUP Publication 4105 for shelf life of preformed
recommended oil temperature and engine rpm.
packings. Most synthetic rubbers are not damaged
by several years of storage under ideal conditions.
To identify defects in the oil system that are
However, they deteriorate quickly when exposed
attributable to either high or low oil pressure, refer
to table 5-3.
to heat, light, moisture, and various other condi-
tions. This is why it is important to keep them in
their original envelopes. Damage also occurs to
REMOVAL AND REPLACEMENT
packings when improperly stored, such as flat-
OF OIL FILTERS
tening or creasing from storage under heavy parts.
Before using the parts, inspect new seals for
The following procedures are general pro-
damage (nicks, scratches, flattening, overage). Do
c e d u r e s . You should refer to the correct
not use overaged, damaged or nonidentifiable
maintenance information manuals before you
seals (seals removed from original envelopes).
remove or replace oil filters on your engine. Oil
The difficulty encountered whenever a gasket,
filters are removed and inspected at regular
seal, or packing is being replaced is in proper
intervals. They are also inspected when the cockpit
installation. Always check that the mating
indicator (chip light) for the magnetic drain plug
surfaces are clean, and that the new gasket, seal,
warns of possible failure.
or packing is correctly installed. Seals or O-rings
are comparatively soft, so you should use care to
1. Provide a suitable container for collecting
prevent nicks and scratches. Do not use sharp
oil and remove the filter (fig. 5-16).
instruments during installation; they could nick
the seals. Always refer to the applicable main-
2. Inspect the filter for metal contamination.
tenance instructions manual for the correct
procedures, tools, and lubricants used during
NOTE: The screen and spacer-type filters
installation.
require a special holding fixture for re-
moving filter elements to prevent stacked
screens and spacers from flying off
ADJUSTMENT OF OIL PRESSURES
assembly.
Before making any oil pressure adjustments,
3. After inspection, clean the filters. Most
you should first check the oil pressure with a direct
filters are routed to AIMD for ultrasonic cleaning.
reading gauge. Record the oil pressure when
4. Install clean or new filters on the oil filter
running the engine at the recommended oil
assembly.
temperature and engine rpm. Oil pressure
adjustments are made with the adjusting screw on
NOTE: The screen and spacer-type filters
the oil pressure relief valve of the oil pump. Turn
require a special holding fixture for
the adjusting screw clockwise to increase and
replacing (buildup) the filter elements. Be
counter clockwise to decrease oil pressure.
sure the screen and spacers are the correct
number and in proper order.
WARNING
5. Install the filter assembly using new O-rings
and gaskets. Torque nuts to recommended values.
Some engines prohibit decreasing oil
pressure; the oil pump must be changed
REMOVAL AND REPLACEMENT
instead. High oil pressure could indicate
blocked oil passages and lowering the oil
OF MAGNETIC DRAIN PLUGS
pressure could result in an inadequate oil
Magnetic drain plugs are usually removed and
supply to some bearings.
inspected at the same time as the main oil filters.
Remove magnetic drain plugs carefully so
Oil pressure adjustments vary between dif-
contaminants will not be disturbed until inspected.
ferent pumps or on pumps with worn parts. One
Figure 5-17 shows two types of magnetic drain
full turn of the adjusting screw equals about 3 psi,
5-19
