TM 5-3895-383-24 Table 15 Caterpillar Minimum Acceptable Water Requirement PPM Water Property mg per liter grains/US gal Max Max Chloride ⁽¹⁾ 40 ⁽¹⁾ 2.4 Sulfate ⁽²⁾ (SO4) 100 5.9 Total Water Hardness ⁽³⁾ 170 10 Total Solids ⁽⁴⁾ 340 20 Acidity ⁽⁵⁾ 5.5 pH to 9.0 pH (1) See "ASTM D51 or "ASTM D4327. (2) See "ASTM D516". (3) See “ASTM D1126”. (4) See "ASTM D1888". (5) See "ASTM D1293”. For a water analysis, consult one of the following organizations: The Caterpillar Laboratory for an SOS Analysis The LOCC Corporation Local water department Agricultural agent Independent laboratory Additives Coolant additives help in the following ways: Preventing rust from forming Preventing scale and mineral deposits from forming Protecting metals from corroding Preventing cavitation of the liner Preventing coolant from foaming Many additives are depleted during engine operation and these additives need to be replaced.  This can be done through the addition  of  Supplemental  Coolant  Additives  (SCA)  to  Diesel Engine  Antifreeze/Coolant  (DEAC)  or  by  adding  Extender  to Extended Life Coolant (ELC). Additives     must     be     added     at     the     proper     concentration. Overconcentration of additives can cause the inhibitors to drop out-of-solution.  This can cause a gel compound to form in the radiator.      An   overconcentration   of   additives   can   produce deposits on water pump seals that can cause water pump seal leakage.    A  low  concentration  of  additives  can  produce  the following problems: Pitting Cavitation erosion Rust Scale Foaming Glycol Glycol  in  the  coolant  provides  anti-boil  protection  and  freeze protection.        Glycol    in    the    coolant    prevents    water    pump cavitation.    Glycol  in  the  coolant  also  reduces  cylinder  liner pitting.  For optimum performance, Caterpillar recommends a solution that contains a 1:1 mixture of water and of glycol. NOTICE All   Caterpillar   diesel   engines   equipped   with   air-to-air aftercooling  (ATAAC)  require  a  minimum  of  30  percent glycol to prevent water pump cavitation. Most conventional heavy-duty coolant/antifreezes use ethylene glycol.  Propylene glycol may also be used.  In a mixture that is 50  percent  water,  ethylene  glycol  and  propylene  glycol  have similar  properties  that  are  relative  to  the  following  elements: heat transfer, freeze protection, control of corrosion, compatibility   with   the   seal.      Check   the   glycol   level   of   the coolant    system    with    the    1U-7298    Coolant/Battery    Tester (Degree  Celsius)  or  with  the  1U-7297  Coolant/Battery  Tester (Degree   Fahrenheit).      Tables   16   and   17   define   the   freeze protection for ethylene glycol and for propylene glycol. Table 16 Ethylene Glycol Concentration Freeze Protection Anti-Boil Protection 50 Percent -36C (-33F) 106C (223F) 60 Percent -51C (-60F) 111C (232F) Table 17 Propylene Glycol Concentration Freeze Protection Anti-Boil Protection 50 Percent -29C (20F) 106C (223F) Maintenance Section Cooling System Specifications 1-24