Reason for High Engine Oil Pressure

TM 9-2320-312-24-2

Testing and Adjusting Section

5. The inlet screen of the oil suction tube for the

1. Check the engine oil level in the crankcase.

engine oil pump can have a restriction. This

The oil level can possibly be too far below the

restriction will cause cavitation and a loss of

oil pump supply tube. This will cause the oil

engine oil pressure. Check the inlet screen on

pump not to have the ability to supply enough

the oil pickup tube and remove any material that

lubrication to the engine components. If the

may be restricting engine oil flow. Low engine oil

engine oil level is low add engine oil in order

pressure may also be the result of the oil pickup

to obtain the correct engine oil level. Refer to

tube that is drawing in air. Check the joints of the

Operation and Maintenance Manual, "Engine Oil"

oil pickup tube for cracks or a damaged O-ring

for the recommendations of engine oil.

seal. Remove the engine oil pan in order to gain

access to the oil pickup tube and the oil screen.

2. Engine oil that is contaminated with fuel or

Refer to Disassembly and Assembly, "Engine Oil

coolant will cause low engine oil pressure.

Pan - Remove and Install" for more information.

High engine oil level in the crankcase can be

an indication of contamination. Determine the

6. Check the following problems that may occur

reason for contamination of the engine oil and

to the engine oil pump.

make the necessary repairs. Replace the engine

oil with the approved grade of engine oil. Also

a. Air leakage in the supply side of the oil

replace the engine oil filter. Refer to Operation

pump will also cause cavitation and loss of

and Maintenance Manual, "Engine Oil" for the

oil pressure. Check the supply side of the

recommendations of engine oil.

oil pump and make necessary repairs. For

information on the repair of the engine oil

NOTICE

pump, refer to Disassembly and Assembly,

Caterpillar oil filters are built to Caterpillar speci-

"Engine Oil Pump - Remove".

fications. Use of an oil filter not recommended by

Caterpillar could result in severe engine damage to

b. Oil pump gears that have too much wear will

the engine bearings, crankshaft, etc., as a result of

cause a reduction in oil pressure. Repair the

the larger waste particles from unfiltered oil entering

engine oil pump. For information on the repair

the engine lubricating system. Only use oil filters

of the engine oil pump, refer to Disassembly

recommended by Caterpillar.

and Assembly, "Engine Oil Pump - Remove".

7. Excessive clearance at engine bearings will

3. If the engine oil bypass valves are held in the

cause low engine oil pressure. Check the

open position, a reduction in the oil pressure

engine components that have excessive bearing

can be the result. This may be due to debris in

clearance and make the necessary repairs.

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

Reason for High Engine Oil

valve in order to correct this problem. You must

Pressure

also clean each bypass valve bore. Install

new engine oil filters. For information on the

repair of the engine oil bypass valves, refer to

NOTICE

Disassembly and Assembly, "Engine Oil Filter

Keep all parts clean from contaminants.

Base - Disassemble".

Contaminants may cause rapid wear and shortened

4. An oil line or an oil passage that is open,

component life.

broken, or disconnected will 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 direct engine oil

toward the bottom of the piston in order to cool the

piston. This also provides lubrication for the piston

pin. Breakage, a restriction, or incorrect installation

of the piston cooling jets will cause seizure of the

piston.