Doosan G643, Руководство по обслуживанию

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G643 (E) Service Manual Chapter 3. Engine Mechanical System 59
Too Much Oil Consumption
•
Engine outside oil leakage
Check for leakage at the seals at each end of the
crankshaft. Look for leakage at the oil pan gasket
and all lubrication system connections. Check to see
if oil comes out of the crankcase breather. This can
be caused by combustion gas leakage around the
pistons. A dirty crankcase breather will cause high
pressure in the crankcase, and this will cause
gasket and seal leakage.
•
Combustion area oil leakage
Oil leakage into the combustion area of the cylinders
can be the cause of blue smoke. There are three
possible ways for oil leakage into the combustion
area of the stems.
1 . Oil leakage between worn valve guides and valve
stems.
2 . Worn or damaged piston rings, or dirty oil return
holes.
3 . Compression ring and/or intermediate ring not
installed correctly.
NOTE : Too much oil consumption can also be the
result if oil with the wrong viscosity is used. Oil with
a thin viscosity can be caused by fuel leakage into
the crankcase, or by increased engine temperature.
Low Oil Pressure
Instrument Panel
(1) Engine Oil Light
Before starting the engine, the engine oil light(1) on
the instrument panel will turn on when the key
switch is turned to the ON position. The light will turn
off after the engine is started and while the engine is
running, lidicating normal oil pressure. The light will
turn on during operation only when there is
insufficient engine oil pressure to properly lubricate
the engine’s internal parts.
If the oil light comes on, indicating the pressure is
low, check for the causes that follow:
1 . Low oil level in the crankcase.
2 . Defect in the oil pressure indicator light or oil
pressure sensor unit.
3 . Restriction to oil pump screen.
4 . Leakage at the oil line connections.
5 . Worn connecting rod or main bearings. Worn
gears in the oil pump.
6 . Oil pressure relief valve worn or stuck in the
OPEN position.
7 . Oil filter bypass valve stuck open. Oil filter is
restricted. Replace oil filter.
High Oil Pressure
Oil pressure will be high if the oil pressure relief
valve in the oil pump cannot move from the closed
position.
Too Much Component Wear
When some components of the engine show
bearing wear in a short time, the cause can be a
restriction in an oil passage. A broken oil passage
can also be the cause.
If an oil pressure check is done and the oil pressure
is correct, but a component is worn because it does
not get enough lubrication, look at the passage for
oil supply to that component. A restriction in a
supply passage will not let enough lubrication get to
a component and this will cause early wear.