it. Operation of the engine with low oil pressure
can he the cause of engine failure or of a reduc-
tion in engine life.
ENGINE OIL PRESSURE CHART
r p m
OF TEST OIL
p s i
k P a
600 to 800
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 to not 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 (the
sudden making of low pressure bubbles 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 can not get to maxi-
mum pressure. Oil pump gears that have too much
wear will cause a reduction in oil pressure.
Oil Filter and Oil Cooler Bypass Valves
If the bypass valve for the oil filter or oil cooler is
held in the open position (unseated) and the oil filter
TESTING AND ADJUSTING
or oil cooler has a restriction, a reduction in oil
pressure can be the result. To correct this problem,
install a new oil filter.
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.
Look for a restriction in the oil passages of the oil
cooler. If the oil cooler has a restriction, the oil
temperature will be higher than normal when the
engine is running. The oil pressure of the engine will
not get low just because the oil cooler has a
OIL PRESSURE IS HIGH
Oil pressure will be high if the bypass valve for the
oil pump can not move from the closed position.
TOO MUCH BEARING WEAR
When some components of the engine show bear-
ing wear in a short time, the cause can be a restriction
in an oil passage. A broken oil passage can also be the
If the gauge for oil pressure shows enough good oil
pressure, but a component is worn because it is not
getting 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 com-
ponent and this will cause early wear.