
44 RENR9968-02
Testing and Adjusting Section
•
The oil suction tube has a leak or a restricted inlet
screen. Refer to Step 5.
•
The engine oil pump is faulty. Refer to Step 6.
•
Engine Bearings have excessive clearance. Refer
to Step 7.
1. Check t he engine oil level in the cran kcase. The
oil level can possibly be too far below the oil pump
supply tube. This will cause the oil pump not to
have th e ability t o supply enough lubrication to the
engine components. If the engine oil level is low
add engine oil in order to obtain the correct engine
oil level. Refer to Operation and Maintenance
Manual for the recommendations of engine oil.
2. Engine oil that is contaminated with fuel or coolant
will cause low engine oil pressure. High engine
oil level in the crankcase can be an indic ation
of contamination. Dete rmine the reason for
contamination of the engine oil and make the
necessary repairs. Replace the engine oil with
the approved grade of engine oil. Also replace
the engine o il filter. Refer to Operation and
Maintenance Manual for the recommendations of
engine o il.
NOTICE
Caterpillar oil filters are built to Caterpillar speci-
fications. Use of an oil filter not recommended by
Caterpillar could result in severe engin e damage to
the engine bearings, crankshaft, etc., as a result of
the larger waste particles from u n filtered oil entering
the engine lu bricating system. Only use oil filters
recomm ended by Caterpillar.
3. If the engine oil bypass valves are held in the
open position, a reduction in the oil pressure can
be the result. This may be due to debris in the
engine oil. If the engine oil bypass valves are
stuck in the open position, remove each engine
oil bypass valve and clean each bypass valve in
order to c orrect this problem . You must also clean
each bypass valve bore. Install new engine oil
filters. Refer to the Disassembly and Assembly
manual for more information on servicing the
bypass valves.
4. An oil line or an oil passage that is open, broken,
or disconnected w ill cause low engine oil pressure.
An open lubrication system could be caused by a
piston cooling jet that is missing or damaged.
Note: The piston cooling jets dire ct engine oil toward
the bottom of the piston in order to cool the piston.
This also provid es lubrication for th e piston pin.
Breakage, a restriction, or incorrect installation of the
piston cooling jets will cause seizure of the piston.
5. The inlet screen of the oil suction tube for the
engine oil pump can have a restriction. This
restriction will cau se cavitation and a loss of
engine oil pressure. Check the inlet screen on
the oil pickup tube and remove any material that
may be restricting engine oil flow. Low engine oil
pressure ma y also be the result of the oil pickup
tube that is drawing in air. Check the joints of the
oil pickup tube for cracks or a damaged O-ring
seal. Remove the engine oil pan in order to gain
access to the oil pickup tube and the oil screen.
Refer to Disassemb ly and Assembly, “En gin e O il
Pan - Remove and Install” for m o re informat ion.
6. Check the following problems that may occur to
the engine oil pump.
a. Air leakage in the supply side of the oil pump
will also cause cavitation and loss o f oil
pressure. Check the supply side of the oil pump
and make necessary repairs. For information
on the repair of the engine oil pump, refer to
Disassembly and Assembly, “Engine Oil Pump
- Remove”.
b. Oil pump gears that have too m uch wear will
cause a reduction in oil pressure. R epair the
engine oil pump. For information on the repair
of the engine oil pump, refer to Disassembly
and Assembly, “Engine Oil Pump - Remove”.
7. Excessive clearance at engine bearings will
cause low engine oil pressure. Check the
engine components that have excessive bearing
clearance and make the necessary repairs.
Reasons for High Engine Oil
Pressure
NOTICE
Keep all parts clean from contaminants.
Contaminants may cause rapid wear and shortened
component life.