Engine Noise And Exhaust Smoke Color; Leakage In The Systems - Isuzu AU-4LE1T Maintenance Manual

Engine noise and exhaust smoke color

Pay attention to engine noise and, if any abnormal noise is heard,
check the engine to detect the cause.
Check the fuel combustion condition by exhaust smoke color.
The exhaust smoke color after engine warming-up and at no-load
operation.
Colorless or light blue.... Normal (Perfect combustion)
Black color..................... Abnormal (Imperfect combustion)
White color .................... Abnormal (Oil coming up and coming down)
CAUTION:
Engine noise after start-up might be noisy than that of
warmed-up engine and, the exhaust smoke color also being
more whitish than the normal condition.
However, it will be normalized after warming-up engine.

Leakage in the systems

CAUTION:
When checking, leaking liquid from engine may be splattered
during engine operation. It may cause a burn. Approach the
engine gradually from a long distance and then check it.
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