Caterpillar Minimum Acceptable
mg per liter
grains/US gal Max
Sulfate (2) (SO4)
Total Solids (4)
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.
The Caterpillar Laboratory for an SOS Analysis
The LOCC Corporation
Local water department
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
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.
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:
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.
Cooling System Specifications