OPERATING IN EXTREME HEAT (Contd)
Check tension adjustment of belts.
Check coolant hoses and lines for cracks, leaks, and security of connections.
Add corrosion inhibitor compound to cooling liquid.
Check for correct tire inflation pressure. Do not reduce pressure if tires are hot from driving.
Reduce lubrication intervals as specified in applicable LOs.
Avoid continuous vehicle operation at high speeds. Avoid long, hard pulls on steep grades with transfer
case shift lever (6) in low.
Frequently check air cleaner indicator (7). If indicator shows red, perform emergency air cleaner
servicing (para. 3-8).
Frequently check engine coolant temperature gauge (8), engine oil pressure gauge (10), and
transmission oil temperature gauge (9). Engine or transmission is overheating if any of the following conditions exist:
Coolant temperature gauge (8) indicates more than 210°F (99°C).
Oil pressure gauge (10) drops below 15 psi (103 kPa) on M939/A1 series vehicles and 10 psi (69
kPa) on M939A2 series vehicles, with engine at idle.
Transmission oil temperature exceeds 300°F (149°C) on oil temperature gauge (9).
If engine overheating occurs:
Do not raise vehicle hood.
Engine will cool faster at
idle with hood closed.
Park vehicle, allowing engine to idle.