TM 5-3805-291-23-1
ENGINE TESTS, INSPECTIONS, AND ADJUSTMENTS - CONTINUED
0010 00
ENGINE OIL PRESSURE TEST - CONTINUED
Reasons for Low Engine Oil Pressure - Continued
5.
If oil pickup tube has a leak or a restricted inlet screen, refer to step 12.
6.
If engine oil pump is faulty, refer to step 13.
7.
If engine bearings have excessive clearance, refer to step 14.
8.
Check the engine oil level in the crankcase (TM 5-3805-291-10). The oil level can possibly 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 com-
ponents. If the engine oil levels is low, add engine oil in order to obtain the correct engine oil level (WP 0025 00).
9.
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 indication of contamination. Determine the reason for contamination of the engine oil and make the
necessary repairs. Replace the engine oil with the approved grade of engine oil (WP 0020 00).
CAU T I ON
Caterpillar oil filters are built to Caterpillar specifications. Use of an oil filter not recommended by Cater-
pillar could result in severe engine damage to the engine bearings, crankshaft, etc., as a result of the larger
waste particles from unfiltered oil entering the engine lubricating system. Only use oil filters recommended
by Caterpillar.
10.
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, replace engine oil filter base
(WP 0028 00) to correct this problem. Install new engine oil filter (WP 0025 00). New engine oil filters will prevent
more debris from causing this problem.
N OT E
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.
11.
An oil line or an oil passage that is open, broken, or disconnected will cause low engine oil pressure. An open lubrica-
tion system could be caused by a piston cooling jet that is missing or damaged. Check for an open lubrication system or
damaged piston cooling jets (WP 0183 00) and make the necessary repairs.
12.
The inlet screen of the oil pickup tube for the engine oil pump can have a restriction. This restriction will cause cavita-
tion 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 may 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 (WP 0181 00) in
order to gain access to the oil pickup tube and the oil screen.
13.
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 of oil pressure. Check the supply
side of the oil pump and replace oil pump if necessary (WP 0182 00).
b.
Oil pump gears that have too much wear will cause a reduction in oil pressure. Inspect oil pump and replace if nec-
essary (WP 0182 00).
c.
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.
0010 00-5
