• 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.
Over concentration 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
For optimum performance, Perkins recommends a
50 percent by volume of glycol in the finished coolant
(also referred to as 1:1 mixture).
Note:
Use a mixture that will provide protection
against the lowest ambient temperature.
Note:
100 percent pure glycol will freeze at a
temperature of −13 °C (8.6 °F).
Most conventional antifreezes use ethylene glycol.
Propylene glycol may also be used. In a 1:1 mixture
with distilled or deionized water, ethylene and
propylene glycol provide similar protection against
freezing and boiling. Refer to Table 9 and refer to
table 10 .
Table 9
Ethylene Glycol
Concentration
Freeze Protection
50 Percent
−36 °C (−33 °F)
60 Percent
−51 °C (−60 °F)
NOTICE
Do not use propylene glycol in concentrations that
exceed 50 percent glycol because of the reduced
heat transfer capability of propylene glycol. Use ethyl-
ene glycol in conditions that require additional protec-
tion against boiling or freezing.
Table 10
Propylene Glycol
Concentration
Freeze Protection
50 Percent
−29 °C (−20 °F)
Some commercially available coolants are based on
alternative fluids, such as 1, 3-propanediol (beta-
propylene glycol, PDO), glycerin (glycerol), or
mixtures of these alternatives with ethylene/
propylene glycols. At the time of publication of this
document no industry standard exists for coolants
based on these chemicals. Until such standard/
specifications are published and evaluated, use of
PDO, glycerine, or other alternative coolants are not
recommended in Perkins engines.
To check the concentration of glycol in the coolant,
measure the specific gravity of the coolant.
Coolant Terminology
• ELC
Extended Life Coolant. A coolant that
relies on organic inhibitors for corrosion and
cavitation protection. Also known as Organic Acid
Technology (OAT) coolant.
• ELI
Extended Life Inhibitor
• SCA
Supplement Coolant Additive,
concentrated inorganic inhibitor package
• ASTM
American Society for Testing and
Materials
• Conventional Coolant
a coolant that relies
on inorganic inhibitors for corrosion and cavitation
protection
• Hybrid Coolant
a coolant in which the
corrosion and cavitation protection is based on a
mixture of organic and inorganic inhibitors.
• Extender
concentrated organic inhibitor
package
Coolant Recommendations
The following three glycol-based coolants are
recommended for use in Perkins diesel engines:
Preferred
– Perkins ELC
M0105633-01
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