Engine Oil - Cessna 1969-1976 172 Series Service Manual

move any sealant remaining in the hole.
drain plug chamber while probing drain plug hole to
ascertain that all residue of sealant material is dis-
lodged and washed out of the chamber. Flushing
operation should last 1 5 t o 30 seconds.
and the drained fuel retained for inspection to insure
that no sealant particles a r e present.
e. Install drain plug as follows:
1. Install drain plug in carburetor 1 -1/2 to 2
turns.
2. Apply NS-40 (RAS-4) MIL-T-5544 (Antiseize,
I
Graphite Petrolatum) or equivalent to plug threads.
3. Tighten and safety drain plug.
f .
Turn fuel valve ON and inspect for evidence of
fuel leakage.
2-21. ENGINE OIL. Check engine lubricating oil
with the dipstick five to ten minutes after the engine
has been stopped. The a i r c r a f t should be in as near
a
level position
as
possible when checking the engine
oil, so that a t r u e reading is obtained. Engine oil
should be drained while the engine is still hot, and
the nose of the a i r c r a f t should be raised slightly for
more positive draining of any sludge which may have
collected in the engine oil sump. Engine oil should
be changed every six months, even though l e s s than
the specified hours have accumulated. Reduce these
intervals for prolonged operations in dusty a r e a s , in
cold climates where sludging conditions exist, o r
where short flights and long idle periods a r e encoun-
tered, which cause sludging conditions. Always
change oil, clean oil screens, and clean and/or
change external filter element whenever oil on the
dipstick appears dirty. Aviation grade oil conforming
t o AVCO Lycoming Specification NO. 301 and Service
Instruction No. 1014, and to any revisions or supple-
ments thereto, shall be used in the "Blue Streak"
(Lycoming) engine. Ashless dispersant oil conform-
ing to Continental Motors Specification MHS-24 and
all revisions or supplements thereto and conforming
with current Continental Aircraft Engine Service
Bulletins shall be used in the Continental engine.
c. Turn fuel valve to ON to flush float chamber and
d. A second flushing should then be accomplished
NOTE
New or newly-overhauled engines should be
operated on aviation grade straight mineral
oil until the f i r s t oil change. If an ashless
dispersant oil i s used in a new or newly-
overhauled engine, high oil consumption may
be experienced. The anti-friction additives
in detergent and dispersant oils will r e t a r d
"break-in" of the pistons, rings and cylinder
walls. This condition can be avoided by the
use of straight mineral oil. The aircraft is
delivered from Cessna with a Corrosion
Preventive Aircraft Engine Oil (MIL-C-6529,
Type 11, RUST BAN). If oil must be added
1
during the f i r s t 25 hours, use only aviation
grade straight mineral oil (non-detergent)
conforming to Specification No. MIL-L-6082.
After the f i r s t 25 hours of operation, drain
engine oil sump and clean both the oil suction
strainer and oil p r e s s u r e screen. If an op-
tional oil filter is installed, change filter
element at this time.
straight mineral oil (non-detergent) and use
until a total of 50 hours have accumulated or
oil consumption has stabilized, then change
Refill sump with
to ashless dispersant oil.
I
When changing engine oil, remove and clean oil
screens, or install a new filter element on aircraft
equipped with a n external oil filter.
An
oil quick-
drain valve may be installed. This valve provides
a quick and cleaner method of draining the engine
oil. This valve is installed in the oil drain port
of the oil sump, and allows oil to be drained by at-
taching a hose over the fitting end and pushing up,
causing the oil to drain through the hose into a con-
tainer. To drain the engine oil, proceed as follows:
a, Operate engine until oil temperature is at nor-
mal operating temperature.
b. (With Quick-Drain Valve.) Attach a hose to the
quick-drain valve i n oil sump. Push upon quick-drain
valve until
it
locks open, and allow oil to drain through
hose into container.
c. (Without Quick-Drain Valve.) Remove oil drain
plug from engine sump and allow oil to drain into
a
container.
valve and remove hose. Install and safety drain
d. After engine oil has drained, close quick-drain
plug.
e. Remove and clean oil screen, or change exter-
f .
Service engine with correct quantity and grade
nal oil filter element.
of engine oil.
NOTE
Refer to inspection charts for intervals
for changing oil and filter elements.
NOTE
Oil capacities for the different models a r e
given i n the following chart. To minimize
l o s s of oil through the breather, f i l l to
specified oil level on dipstick for normal
operation (flight of l e s s than three hours
duration). For extended flight, f i l l to FULL
mark on dipstick. Do not operate with l e s s
than MINIMUM- FOR- FLIGHT quantities
listed. If an external oil filter is installed,
one additional quart of oil
is required when
filter element is changed.
MODEL CAPACITY CAPACITY (TOTAL NORMAL MINIMUM
OPERATION FOR FLIGHT
(TOTAL) WITH FILTER)
m
172 8 9
7
6
Change 3 2-7