Piper PA-24 Comanche Service Manual page 475

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PIPeR COMANCHE SeRV\CE MANUAL
1C-68. Oil Cooler.
a.
When conduetin.
a
routine encine inspection, the oil eeeler, lines and fittings should be checked
for the foUowinJ:
1. Oil cooler line attachments should be examined to be Ceru1D thu all are
~ilht
and there is no
indication oi crOSltbreadinJ. (Sec C for oil line torque.)
2. Oil lines mua have adequate clearance and be properly aliped.
3. Oil line supportS should
be
titbt. property
positioned
and if wom should be
replaced,
~.
Oil cooler should
be
checked for
I~
or discon:ed
cells.
, . Coolin. fiDs should be clean &ad unclamqcd.
b. Dunn, each cupne overhaul; atindicuions of bith oiltntpentures or dunn,
a
500 hour
inspection. the oil cooler should be
removed; daned
aDd checked for dam.d
fltlS
and cells. When
replac:m, the cooler. properly
a1ipl
aDd do not over tilinen the mOWltifti bolts
so
that the cooler would be
e:tamaccd. While the oil cooler is removed. the oil lina should be dUcoMected
and
flushed.
c. If it is found that oil is leaking around the line compression nua. cbeck that the nuts
arc
tilhtened
to 125 inch pound
Wet
torque or the nut may be backed off. rctiPtened
ftlll"
tiCht, plus
a
314
tum. Do
nOt over torque.
d. Should oil continue to leak. it may be necessary to replace the seal
rings. Also
remove
the
c;ompression nuts and inspect the line
ends in
the
area
of the swaged ferrules for collapsed rubin,. This
condition may
be
observed by lookq intO the cubint ends. Should the the cubing show indications that It
is collapsed and
new scaI rinp
and proper torque does not StOp lcakap. the oillincs should be replaced.
Also inspect the surfaces of the mann,
fininp
for
dam • .
7C-69. Recommendations For Chanlina Oil.
(Ref. latest
Lye. S.l. No. 1014.)
a. If an additive oil is wed in a new eDJinc.
OT
a newly ovcmauled engine. high oil consumption
miJht possibly
be
experienced. The antiofrietion additives of some oi these oils will retard the break-in oi
the piston rinp 1I\d cylinder walls. This condition is easily eerreeted by the usc of straight mineral
011
until
normal oil consumption is obtained, then
ehanF
to the additive
type.
b. In erlJincs that have been opcratirlJ on sttailht mineral oil for more than 100 houn.
a
ch<Lnte to
detergent oil should be made with a degree of caution, the deaning ac:tion of a detCfJent oil
will
tend to
loosen sludge deposia and caUsc pluacd oil pusqcs. In fact. if an engine has been operanng on
stra~i\t
mineral oil. and
1$
known to be in cxcessividy dirty condition. the switch to detergent
011
should be deren-cd
until after the enpne is overhauled.
c. When chanlin, from straight
mincraJ
oU to detergent oil, the following precautionary steps should
be taken:
1. Do not add detergent oil
ee
Straight mineral oil. Drain the straight minen.1 oil from the eftilne
ancl rill with detergent oil.
2. Do not operate the cngine lonpt than five hours before the
fim
oil change..
3. Check oil screen <Lnd filter for evidence of sludge or pluaing. Change oil every tcn hours if
sludge conditions arc evidenr, Resume normal oil drain periods after slild,c ccndinons improve.
POWER PLANT
REVISED: 4/10/81
2
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