Engine Maintenance
97
Low Oil Pressure
Oil pressure is affected by oil temperature, oil
viscosity, and engine speed. Low oil pressure can
usually be traced to the lack of oil, a faulty oil
pressure regulating valve, or worn bearings. Low
oil pressure is not normally caused by a faulty oil
pump. Use the “Low Oil Pressure Flow Chart” on
the following page to help diagnose low oil
pressure.
Low Oil Pressure Flow Chart
Low Oil Pressure
Check Oil Level
Full
Low
Add oil until full.
Re-check oil pressure in
low and high speed.
Check for oil dilution.
Is it just thin or does it
smell like fuel?
OK
Verify the unit switch,
sensor, or gauge
accuracy using a test
gauge.
Accurate
Not
Accurate
Repair and
re-check oil pressure in
low and high speed.
Diluted
with Fuel
Check for excessive
radial end play at the
flywheel with a dial
indicator. Maximum;
0.007 in. 4-cylinder.
Excessive
OK
Drain oil through a
clean coffee filter and
check for wear metal
contamination.
No Wear
Metal
Thin
See
EDP08
Fuel in Oil
Change oil and filter.
Re-check oil pressure
in low and high speed.
OK
Low
Repair or
replace engine.
Wear Metal
Present
Check oil pressure regulator
or oil pressure control valve
and repair or replace as
necessary. Re-check oil
pressure in
low and high speed. If oil
pressure is still low, repair or
replace engine.
ARA1368
