d. Electrical System Protection. Check the specific gravity reading of the battery electrolyte frequently. Keep the
batteries as fully charged as possible. Refer to paragraph 90 for detailed battery maintenance.
Caution: In freezing weather, when adding water to electrolyte, run the engine for about 20 minutes to assure a ;roper
electrolyte solution. Water not in solution will freeze, expand, and ruin the battery.
35. Operation in Extreme Heat
a. Cooling System Protection. Keep the radiator well filled with clean, soft water, and see that the fins of the radiator
and the aftercooler are free from foreign material. Check the operation of the radiator shutters with the water temperature
gage on the instrument panel. The radiator shutters should open when engine water temperature is approximately 180° F.
Add water to the radiator only when the engine is stopped and cool, or idling, with moderate water temperature. Fill the
radiator only to the height of the baffle. Check hoses and connections periodically for possible leaks.
b. Special Lubrication Instructions. Select the correct lubricants in accordance with the expected air temperature as
indicated in the lubrication order (fig. 16).
36. Operation Under Dusty or Sandy Conditions
a. Check Air Cleaners. Dust may enter the unit through several channels; at the air .intake, engine breather, or from
dust contamination of oil, water, or fuel. Remove the filters from the engine air cleaners (par. 76) and compressor air
cleaners (par. 123) as often as every 2 to 4 hours and clean thoroughly.
b. Check Oil-Filler and Breather Cap. At least every 2 to 4 hours remove and clean the combination oil-filler and
engine breather cap. This will help to eliminate the entrance of dust and sand into the engine crankcase.
c. Protect Stores of Oil, Water, and Fuel. Stored supplies of oil, water, and fuel must be kept tightly covered to
protect these supplies from sand and dust contamination. If possible, keep such supplies in an inclosure such as a shed
or storage room.
37. Operation in Salt Water Area
a. Submersion in Salt Water. If the unit has been submerged in salt water, electrical equipment and metal parts will
be damaged to such an extent that complete rebuilding or replacement of assemblies will be necessary. If all traces of salt
water can be removed at once, it may be possible to salvage certain units
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