ENGINE TESTS, INSPECTIONS, AND ADJUSTMENTS - CONTINUED
ENGINE OIL PRESSURE TEST - CONTINUED
N OT E
Oil level can be too far below oil pump supply tube, in which case oil pump will not supply enough
lubrication to engine components. If engine oil level is low, refer to step 1.
Engine oil contaminated with fuel or coolant will cause low engine oil pressure. High engine oil
If engine oil bypass valves are held in open position, a reduction in oil pressure can result. This
may be due to debris in engine oil. If engine oil bypass valves are open, refer to step 3.
An oil line or oil passage that is open, broken, or disconnected will cause low engine oil pressure.
An open lubrication system could be caused by a missing or damaged piston cooling jet. If engine
lubrication system is open, refer to step 4.
The oil pickup tube inlet screen for the engine oil pump can have a restriction. This restriction
will cause cavitation and loss of engine oil pressure. If oil pickup tube has a restricted inlet screen,
refer to step 5.
Low engine oil pressure may also be a result of an oil pickup tube that is drawing in air. If oil
pickup tube has a leak, refer to step 6.
Wear, damage, or air leakage in engine oil pump will cause cavitation and loss of oil pressure. If
engine oil pump is defective, refer to step 7.
Excessive clearance at engine bearings will cause low engine oil pressure. If engine bearings are
suspected to have excessive clearance, refer to step 8.
Low Oil Pressure
Check engine oil level in crankcase (TM 5-3805-290-10). If engine oil level is low, add engine oil to correct engine oil
level (WP 0025 00).
Determine reason for engine oil contamination and make necessary repairs. Drain contaminated oil and fill with proper
grade of engine oil (WP 0025 00). If engine oil is contaminated with fuel or coolant it will cause low engine oil pressure.
High engine oil level in crankcase can be indication of contamination.
C AU T I O N
Use only oil filters designed for this machine. Using any other oil filter may result in damage to internal
Remove and clean each bypass valve to correct problem. Replace engine oil bypass valve(s), as necessary (WP 0158
00). Install new engine oil filters (WP 0025 00).
Determine reason for open engine lubrication system and make necessary repairs. Refer to appropriate work package.
N OT E
Piston cooling jets direct engine oil toward bottom of piston to cool piston. This also provides lubrica-
tion for piston pin. Breakage, restriction, or incorrect installation of piston cooling jets will cause sei-
zure of piston.
Remove engine oil pan (WP 0157 00) to gain access to oil pickup tube and oil screen.