TM-9-2320-387-10 HMMWV Operator Manual Download
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TM 9-2320-387-10 Change 1 2-111 c. During Operation. CAUTION Avoid continuous vehicle operation at high speeds. Avoid long, hard pulls on steep grades with transfer case shift lever in L (low range) position. Damage to transfer case will result. (1) Frequently check coolant temperature gauge (2) and oil pressure gauge (1). Engine is overheating if one or more of the following conditions exist: (a) Engine coolant temperature is more than approximately 230°F (110°C) as indicated by temperature gauge (2). (b) Engine oil pressure drops below approximately 15 psi (103 kPa) with engine under a load. (c) Engine oil pressure drops below approximately 6 psi (41 kPa) with engine at idle. (2) If engine overheating occurs: (a) Park vehicle, allowing engine to idle. (b) Observe coolant temperature gauge (2) for steady cooling. CAUTION • Stop engine if coolant temperature gauge suddenly increases beyond approximately 230°F (110°C). Failure to comply will result in damage to engine. • Notify unit maintenance to check differentials, transfer case, and transmission fluids for “oil breakdown” caused by overheating. (c) If engine coolant temperature continues to increase or does not lower, stop engine. Perform troubleshooting procedures in table 3-1. 1 2