TM 5-3895-383-24
Oil Gallery Plug
(1) Plug.
Work carefully around an engine that is running. Engine
parts that are hot, or parts that are moving, can cause
personal injury.
Oil pressure to the camshaft and main bearings should be
checked on the side of the cylinder block at oil gallery plug (1).
Install the adapter, seal, reducing bushing, and the 1U5470
Engine Pressure Group to this opening. With the engine a
operating temperature (using SAE 10W30 oil), under full load
condition, minimum oil pressure should be 200 kPa (36 psi).
With the engine at operating temperature (using SAE 10W30
oil), at 750 to 850 rpm low idle, minimum oil pressure is 100
kPa (15 psi). With the engine at operating temperature (using
SAE 10W30 oil), under full load condition, maximum oil
pressure is 600 kPa (88 psi).
Oil Pressure Is Low
Crankcase Oil Level
Check the level of the oil in the crankcase. Add oil if needed.
It is possible for the oil level to be too far below the oil pump
supply tube. This will cause the oil pump not to have the ability
to supply enough lubrication to the engine components.
Oil Pump Does Not Work Correctly
The inlet screen of the supply tube for the oil pump can have a
restriction. This will cause cavitation (low pressure bubbles
suddenly made in liquids by mechanical forces) and a loss of
oil pressure. Air leakage in the supply side of the oil pump will
also cause cavitation and loss of oil pressure. If the bypass
valve for the oil pump is held in the open (unseated) position,
the lubrication system cannot get to maximum pressure. Oil
pump gears that have too much wear will cause a reduction in
oil pressure.
Oil Filter Bypass Valve
If the bypass valve for the oil filter is held in the open position
(unseated) because the oil filter has a restriction, a reduction in
oil pressure can result. To correct this problem, remove and
clean the bypass valve and bypass valve bore. Install a new
Caterpillar oil filter to be sure that no more debris makes the
bypass valve stay open.
Too Much Clearance At Engine Bearings Or Open
Lubrication System (Broken Or Disconnected Oil Line Or
Passage)
Components that are worn and have too much bearing
clearance can cause oil pressure to be low. Low oil pressure
can also be caused by an oil line or oil passage that is open,
broken or disconnected.
Piston Cooling Jet Tube
When the engine is operated, cooling jet tubes direct oil toward
the bottom of the piston to cool the piston and also provide
lubrication for the piston pin. If a cooling jet tube is broken,
plugged or installed wrong, seizure of the piston will be caused
in a very short time.
Oil Pressure Is High
Oil pressure will be high if the bypass valve for the oil pump
cannot move from the closed position.
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