TM 5-2420-230-24-2
Turbocharger (010-033)
B3.9 and B5.9 Series Engines
Page 10-30
Section 10 - Air Intake System - Group 10
Additionally, high intake or exhaust restrictions can cause
a vacuum between the compressor and the turbocharger
housing, resulting in oil leaking past the seals.
To verify lubricating oil leakage past the seals, remove the
exhaust pipe and crossover tube, and check for lubricating
oil in the turbine casing and the crossover tube. Locate and
correct the restriction as previously discussed.
Turbocharger Noise
It is normal for the turbocharger to emit a ``whining'' sound
that varies in intensity depending on engine speed and
load. The sound is caused by the very high rotational speed
of the rotor assembly. Consequently, the sound will become
more audible at full speed.
If possible, operate the engine at full speed to verify the
noise level.
Leaks in the air system intake and/or exhaust components
can produce additional noises.
Pressurize the intake system, and check for air intake and
crossover tube leaks.
L-1154