ENGINE SMOKES (BLUE SMOKE) DURING START, OPERATION AND SHUTDOWN.

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3-2. TROUBLESHOOTING - CONTINUED

E S - 2 1 . ENGINE SMOKES (BLUE

(5)

d. ENGINE - CONTINUED

S M O K E ) DURING START, OPERATION

AND SHUTDOWN.

This section contains troubleshooting to locate and correct the cause(s)

of blue smoke from the exhaust during start, operation and shutdown.

Blue smoke is an indication of oil leakage past seals in,oil-wetted

areas into the exhaust path of the engine. This symptom is,usuallY

accompanied by excessive oil consumption. Many of the bearing packages

in the engine are air pressurized to assist the carbon face seals in

sealing oil-wetted areas. If carbon face seals or packings do not seal

properly, leakage will not occur past the seal if the air pressure is

higher than the oil pressure in that package. Once the alr pressure

becomes lower than the oil pressure, oil w1ll leak past the seal. When

carbon face seals or packings are severely damaqed, alr,pressure may

prove insufficient to prevent 0il leakage, causing continuous smoke

during start, operation and shutdown. The art on the following pages

provides an overview of the exhaust system and related components. Refer

to these pages along with in-text art while performing troubleshooting.

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