NOTICE
Frequently check the specific gravity of the coolant
for proper freeze protection or for anti-boil protection.
Clean the cooling system for the following reasons:
• Contamination of the cooling system
• Overheating of the engine
• Foaming of the coolant
NOTICE
Never operate an engine without water temperature
regulators in the cooling system. Water temperature
regulators help to maintain the engine coolant at the
proper operating temperature. Cooling system prob-
lems
can
develop
without
water
temperature
regulators.
Many engine failures are related to the cooling
system. The following problems are related to cooling
system failures: Overheating, leakage of the water
pump and plugged radiators or heat exchangers.
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.
Water
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
12 .
Table 12
Acceptable Water
Property
Maximum Limit
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.
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
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 −13 °C (8.6 °F).
68
SEBU9075-03
