TM 5-4320-300-14
Table 6-1. General Support Maintenance Troubleshooting - Continued
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
Step 4. Check for piston and rod alignment. Inspect pistons and connecting rods (para 6-10). Check crankshaft
thrust surfaces and thrust washers for wear or grooving (para 6-11).
Replace a faulty piston or connecting rod (para 6-10). If necessary, regrind and polish crankshaft
and install oversize thrust washers (para 6-11).
3. ENGINE PRODUCES EXCESSIVE CRANKCASE PRESSURE
Step 1. Check for worn piston rings, a hole or crack in a piston crown, worn blower oil seals, defective blower, or
excessive exhaust back pressure.
Replace worn or damaged parts (para 6-4 and 6110).
4. ENGINE HAS LOW OIL PRESSURE
Step 1.
Check for clogged oil cooler core. Inspect oil cooler core (para 6-4).
Replace a clogged or otherwise faulty oil cooler core (para 6-4).
Step 2.
Check for malfunctioning oil cooler bypass valve or pressure regulator valve. Inspect valves (para
6-6).
Repair or replace faulty valves (para 6-6).
Step 3.
Check for partially clogged oil pump inlet screen. Inspect oil pump inlet screen (para 6-6).
Replace a screen that is damaged or cannot be cleaned adequately (para 6-6).
Step 4.
Check for air leak in oil pump inlet pipe and screen assembly. Inspect oil pump inlet pipe and screen
assembly (para 6-6).
Repair or replace a faulty oil pump inlet pipe and screen assembly (para 6-6).
Step 5.
Check for worn or damaged oil pump. Inspect oil pump (para 6-6).
Repair or replace a faulty oil pump (para 6-6).
Step 6.
Check for missing crankshaft oil plugs, or excessive wear on crankshaft main bearing journals or
bearings. Inspect crankshaft (para 6-11). Inspect main bearings (para 6-12).
Replace missing crankshaft plugs. Regrind or replace faulty crankshaft (para 6-11). Replace main
bearings, if necessary (para 6-12).
Step 7.
Check for missing camshaft plugs. Inspect camshaft (para 6-9). Replace missing camshaft plugs
(para 6-9).
6-4
