SEBU8337 39
Maintenance Section
Refill Capacities
Water
Water is used in the cooling system in order to
transfer heat
.
Distilled water or deionized water is
recommended f
or use in engine cooling systems.
DO NOT use the following types of water in cooling
systems: Hard
water, softened water that has been
conditioned with salt, and sea water.
If distilled
water or deionized water is not available,
use water with the properties that are listed in Table 5.
Table 5
Acceptable Water
Property Maximum L imit
Chloride (Cl) 40 mg/L
Sulfate (SO
4
) 100 mg/L
Total Hardness 170 mg/L
Total Solids 340 mg/L
Acidity
pH of 5.5 to 9.0
For a water analysis, consult one of the following
sources:
•
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
•
Foaming of the coolant
Many additives are depleted during engine operation.
These additives must be replaced periodically.
Additives must be added at the correct concentration.
Overconcentration of additives can cause the
inhibitors to drop out-of-solution. The deposits can
enable the following problems to occur:
•
Formation of ge
l compounds
•
Reduction of heat transfer
•
Leakage of the water pump seal
•
Plugging of ra
diators, coolers, and small passages
Glycol
Glycol in the coolant helps to provide protection
against the following conditions:
•
Boiling
•
Freezing
•
Cavitation of the water pump
For optimum performance, Perkins recommends a
1:1 mixture of a water/glycol solution.
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 antifreezes use ethylene glycol.
Propylene glycol may also be used. In a 1:1 mixture
with water, e
thylene and propylene glycol provide
similar protection against freezing and boiling. See
Tables 6 and 7.
Table 6
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.
Table 7
Propylene Glycol
Concentration
Freeze
Protection
Anti-Boil
Protection
50 Percent −29 °C (−20 °F) 106 °C (223 °F)
To check the concentration of glycol in the coolant,
measure the specific gravity of the coolant.
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