TM9-2320-361-34 Table 2-1. Mechanical Troubleshooting (Contd). MALFUNCTION TEST OR INSPECTION CORRECTIVE ACTION Hot coolant is under pressure. Care should be used when removing coolant filler cap or inspecting hot engine coolant leaks. Steam or hot coolant under pressure may cause severe injury to personnel. Step 2. Pressure test warm engine cooling system (TM 750-254). Observe pressure tester reading. a. b. c. If pressure tester reading declines and there are no indications of external leaks, coolant is leaking internally into engine or combustion chambers. Remove oil dipstick and check engine oil for presence of coolant. If coolant is present on oil dipstick, check intake manifold and gasket for defects (malfunction 1, step 9). Check cylinder heads and gaskets for defects (malfunction 1, step 10b). NOTE When engine exhaust color remains white during test run after cylinder heads or gaskets replacement, internal engine block cooling jacket failure is indicated. Replace engine (para. 3-18). END OF TESTING! 13. ENGINE OIL PRESSURE LOW OR ZERO AT NORMAL OPERATING TEMPERATURE CAUTION Do not operate engine except during testing when condition of no oil pressure is evident. Continued operation may damage engine internally. Step 1. Check oil pressure regulator for leaks or defective operation. Remove oil pressure regulator and inspect (para. 3-13). If oil pressure regulator is defective, replace (para. 3-13). NOTE When oil pump operation or condition becomes defective, usually there is a lack of oil supply or restriction from oil sludge. Step 2. Check oil pump operation and condition. Remove oil pan and oil pump (paras. 3-11 and 3-12). Inspect oil pump (TM 9-2815-210-34-2-2). If oil pump is defective, replace (para. 3-12) or repair oil pump (TM 9-2815-210-34-2-2). Do not install oil pickup or oil pan. Step 3. Check oil pickup for restrictions. If oil pickup is restricted, clean or replace (para. 3-12). Do not install oil pan. NOTE Lack of oil supply due to oil pickup restrictions reducing or cutting off oil supply may cause damage to main and rod bearings, crankshaft, and rods. Step 4. Inspect crankshaft for nicks, burns, grooves, scuffs or discoloration due to overheating. If damaged, replace engine (para. 3-18). 2-11