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46
Maintenance Section
General Coolant Information
These failures can be avoided with correct cooling
system maintenance. Cooling system maintenance is
as important as maintenance of the fuel system and
the lubrication system. Quality of the coolant is as
important as the quality of the fuel and the lubricating
oil.
Coolant is normally composed of three elements:
Water, additives, and glycol.
Refer to Perkins Diesel Engines Fluids
Recommendations, M0113102 for additional
information that relates to coolant.
Water
NOTICE
Never use water alone as coolant. Water alone is cor-
rosive and does not provide any protection against
boiling or freezing.
Water is used in the cooling system to transfer heat.
Distilled water or deionized water is
recommended for 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 7
.
Table 7
Perkins Minimum Acceptable Water Requirements
Property
Maximum Limit
Chloride (Cl)
40 mg/L
Sulfate (SO
)
100 mg/L
4
170 mg/L
Total Hardness
340 mg/L
Total Solids
Acidity
pH of 5.5 to 9.0
(1)
Total dissolved solids dried at 103° C (217° F) - 105° C
(221° F), "Standard Method for the Examination of Water and
Wastewater", "American Public Health Association", "www.
apha.org", "www.aphabookstore.org", (888) 320-APHA.
For a water analysis, consult one of the following
sources:
• Local water utility company
• Agricultural agent
• Independent laboratory
Periodic analysis of water that is used to add to the
coolant is recommended. Water quality can be
affected by various factors including malfunctioning
purification equipment, earthquakes, and droughts.
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
• 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
ASTM Test
Glycol in the coolant helps to provide protection
"D4327"
against the following conditions:
"D4327"
• Boiling
"D1126"
• Freezing
"Federal Method
2540B"
(1)
• Cavitation of the water pump
"D1293"
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 water, ethylene and propylene glycol provide
similar protection against freezing and boiling. Refer
to Table 8 and refer to table 9 .
liner
M0122761
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