Cessna 188 Series Service Manual page 170

MODEL 188 & T188 SERIES SERVICE MANUAL
11-32. FULL-FLOW OIL FILTER.
(1880001 THRU
NOTES
18803473) (See figure 11-3.)
When installing a new filter element, it is im-
11-33. DESCRIPTION. An external oil filter may portant that all gaskets are clean, lubricated
be installed on the engine. The filter and filter
and positioned properly, and correct amount
adapter replaces the regular internal oil pressure
of torque is applied to filter hollow stud.
If
screen. In some filter installations, the filter adap-
stud is under-torqued, oil leakage will occur.
ter incorporates a bypass valve, outlet valve and
If stud is over-torqued, the filter can may be
isolation valve. Normally, oil from the oil pump
deformed, again causing oil leakage.
flows through the isolation valve, through the filter
element, through the outlet valve, to the engine oil
passages.
If the filter element should become block-
ed, the bypass valve and outlet valve will open, allow-
*Lubricate rubber grommets in each end of
ing pressure oil to flow to the engine oil passages.
new filter element, rubber gaskets (13, 17)
The isolation valve blocks off the filter assembly and
and metal gasket (22) with a thin coating of
oil then flows through the bypass valve, if excessive
Dow Corning Compound, DC-4, apply by
oil pressure should occur.
In some filter installa- brushing or wiping lubricant on base gasket.
tions the filter adapter incorporates only a bypass
valve.
Before assembly, place a straightedge across
bottom of filter can. Check for a distortion
11-34. ELEMENT REMOVAL AND INSTALLATION.
or out-of-flat condition greater than .010 inch.
(See figure 11-3.)
Replace if either of these conditions exist.
NOTE
* Before assembly, cut adapter nut safety wire
and try to rotate adapter by hand. If adapter
New filter kits are available from the Cessna
can be moved, check for thread deformation
Supply Division.
in engine and adapter.
a. Remove engine cowling in accordance with para-
· After installing a new gasket on lid (16),
graph 11-3.
turn it upside down. If gasket falls, try
b. Remove safety wires from filter can and unscrew
a different gasket and repeat test. If
hollow stud (23) to detach filter assembly from adapter
this gasket falls off, install a new lid.
(5) as a unit.
Remove filter assembly from aircraft,
discarding upper gasket (13).
Oil will drain from
g. Inspect adapter gasket seat for gouges, deep
filter as assembly is removed from adapter. scratches, wrench marks and mutilation.
If any of
c. Press downward on stud (23) to remove from
these conditions are found, install a new adapter.
filter element (18) and can (19). Discard metal
h. Place new element in can and insert stud (23)
gasket (22) on stud (23).
with a new metal gasket (22) in place, through the
d. Lift lid (16) from can (19) and discard lower can and element.
gasket (17). i. Position a new gasket (17) inside lower flange of
e. Pull filter element (18) from can (19) and dis- lid (16). Position new gasket (13) around upper flange
card.
of lid (16). Place the lid in position.
j. Install filter assembly on adapter. Holding can
NOTE to prevent it from turning, tighten stud (23) and torque
to 20-25 lb-ft (240-300 lb-in), using a torque wrench.
Before discarding removed filter element, re- k. Reinstall parts removed for access and service
move the outer perforated paper cover; using the engine with proper grade and quantity of oil.
One
a sharp knife, cut through the folds of the fil-
additional quart of oil is required each time the ele-
ter element at both ends, close to the metal ment is replaced.
caps. Then carefully unfold the pleated ele-
1. Start engine and check for proper oil pressure.
ment and examine the material trapped in the Check for oil leakage after warming up engine.
filter element for evidence of internal engine
m. Again check for oil leakage after engine has been
damage such as chips or particles from bear- run at a high power setting (preferably a flight around
ings. In new or newly overhauled engines, the field).
some small particles or metallic shavings n. Check to make sure that the filter has not been
might be found. These are generally of no
in contact with adjacent parts due to engine torque.
consequence and should not be confused with
o. While engine is still warm, recheck torque on
particles produced by impacting, abrasion
stud (23), then safety stud to lower tab (21) on filter
or pressure. Evidence of internal engine
can and safety adapter to upper tab (20) on filter can.
damage found in the oil filter element justifies
further examination to determine the cause. 11-35. ADAPTER REMOVAL.
(See figure 11-3.)
a. Remove filter assembly as outlined in paragraph
f. Wash lid (16), hollow stud (23) and can (19) in
11-34.
cleaning solvent and dry with compressed air.
b. Note angular position of adapter, then remove
safety wire and loosen adapter nut (2).
11-14 Revision I