PS Magazine - MARCH 1982

PS, The Preventative Maintenance Monthly

ISSUE 352

MARCH 1982

PS Magazine - MARCH 1982 - Page 21 of 35
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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