3Com Caterpillar Commercial Diesel Engine SEBU6251-06 - Manual (Page 25)

25
Maintenance Section
Cooling System Specifications
Table 9
Caterpillar Minimum Acceptable Water Requirements
Property Maximum Limit ASTM Test
Chloride (Cl)
40 mg/L
(2.4 grains/US gal)
“D512”,
“D4327”
Sulfate (SO
4
)
100 mg/L
(5.9 grains/US gal)
“D516”
Total Hardness
170 mg/L
(10 grains/US gal)
“D1126”
Total Solids
340 mg/L
(20 grain/US gal)
“D1888”
Acidity pH of 5.5 to 9.0 “D1293”
For a water analysis, consult one of the following
sources:
• Caterpillar dealer
• Local water utility company
• Agricultural agent
• Independent laboratory
Additives
Additives help to protect the metal surfaces of
the cooling system. A lack of coolant additives
or insufficient amounts of additives enable the
following conditions to occur:
• Corrosion
• Formation of mineral deposits
• Rust
• Scale
• Pitting and erosion from cavitation of the cylinder
liner
• Foaming of the coolant
Many additives are depleted during engine
operation. These additives must be replaced
periodically. This can be done by adding
Supplemental Coolant Additives (SCA) to Diesel
Engine Antifreeze/Coolant (DEAC) or by adding
ELC 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. The
deposits can enable the following problems to
occur:
• Formation of gel compounds
• Reduction of heat transfer
• Leakage of the water pump seal
• Plugging of radiators, coolers, and small
passages
Glycol
Glycol in the coolant helps to provide protection
against the following conditions:
• Boiling
• Freezing
• Cavitation of the water pump and the cylinder liner
For optimum performance, Caterpillar recommends
a 1:1 mixture of a water/glycol solution.
NOTICE
All Caterpillar diesel engines equipped with air-to-air
aftercooling (ATAAC) require a minimum of 30 percent
glycol to prevent water pump cavitation.
Note: Use a mixture that will provide protection
against the lowest ambient temperature.
Note: 100 percent pure glycol will freeze at a
temperature of
−
23

C (
−
9

F).
Most conventional heavy-duty coolant/antifreezes
use ethylene glycol. Propylene glycol may also be
used. In a 1:1 mixture with water, ethylene and
propylene glycol provide similar protection against
freezing and boiling. See Tables 10 and 11.
Table 10
Ethylene Glycol
Concentration
Freeze
Protection
Boil
Protection
50 Percent
−
36

C (
−
33

F) 106

C (223

F)
60 Percent
−
51

C (
−
60

F) 111

C (232

F)
NOTICE
Do not use propylene glycol in concentrations that ex-
ceed 50 percent glycol because of propylene glycol’s
reduced heat transfer capability. Use ethylene glycol
in conditions that require additional protection against
boiling or freezing.