PS Magazine - MARCH 1982
PS, The Preventative Maintenance Monthly
ISSUE 352
MARCH 1982
EngiNe ChaNge?
Never rush into changing a leaky T5± engine in your Chinook, knu²kle-
busters. ·You can fIx i³ yourself and save Uncle a Bundle.
Those babies have a history of static oil leaks aftE
´
r they're shut dOwnµ
Mo¶s³ of them are ³he result of oiL seeping past the ¸o.
1
bearing seals.
When ³he ¹ngine is running, the seals are pressurizºd by compressor
Problem
...
The No.
±
bearing seals »an¼t Be replaced in the field. More than likely,
³ho, the oil leak is caused by any one of the foLlowing:
•
Oil wiLL Leak past the main oiL pump pressure baLl cHeck
valve if dirt or otHer deposits prevent the balL from seating.
•
OiL may leak past the N2 overspeed
•
Oil may leak pasT the ou±put shaft
controL outer bevel-driven gear Liner seaL, seaL air inlet adapter pacKings, Item 4, 5,
lten² 45, Fig 6³3, ´M 55-2840-234µ24/2. 5A, 6 in FiG 5¶42 of tHe engine pub.
J
bleed air½no LeaKs.
¾hen the engine is sh¿t down, only seal contact pressure remains. So
³he seals give way if the No.
1
bearing packing becomes fiLled with oil. The
resul³ is an oiL s³reak a³ ³he inle³ housing, which ends up in a puddle on the
To find ³he leak and correc³ ³he
probLem, ³ake ³hese troubLesHoo³iÀg
s³epsÁ
•
Remove the oiL line aTtHe inLeTTo The
oiL cooLer. Secure tHe end of the Line
beLow the center line of the engine and LeT
the Line dr·in for one hour. ´hen check
tHe rate at wHicH oil drips from the line. If
you geT one drop or more within 1_5
seconds, The oiL pump check vaLve ¸s
stuck open.
´He valve may re¶seat when thE engine
·
is operated again¹ If not, change the oil
pump.
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