TM 9-2320-209-20-3-1 Table 6-1. Guide for Preparation of Antifreeze Solution. Ethylene-glycol (- 60°F ) inhibited (O-A-548) Lowest expected ambient Quarts per gallon temperature of coolant capacity Specific gravity Arctic grade antifreeze (°F) (Notes 1, 2) (68°F) (-90°F) MIL-A-11755 +20 3/4 1.022 Freezing point of -90°F. +10 1 1.036 Issued ready for use and must 0 1 1/3 1.047 not be mixed with any other -l0 1 2/3 1.055 liquid. -20 1 3/4 1.062 -30 2 1.067 -40 2 1/8 1.073 -50 2 1/4 -60 2 1/3 Below -60 Use arctic grade antifreeze (-90°F) NOTES : 1. Includes heaters. 2. Proportions are in terms of ethylene-glycol per gallon and not quarts of ethylene-glycol added to each gallon of water. For example, at –30°F a gallon of coolant contains two quarts of ethylene–glycol and two quarts of water ( 2 quarts + 2 quarts = 4 quarts = 1 gallon).