Perkins 402F-05 Operation And Maintenance Manual page 39

SEBU9064
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 in order 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
16 .
Table 16
Acceptable Water
Property
Chloride (Cl)
Sulfate (SO )
4
Total Hardness
Total Solids
Acidity
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:
Maximum Limit
40 mg/L
100 mg/L
170 mg/L
340 mg/L
pH of 5.5 to 9.0
• 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 −23 °C (−9 °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 17 and refer to table 18 .
Table 17
Ethylene Glycol
Concentration
50 Percent
60 Percent
39
Refill Capacities
Fluid Recommendations
Freeze Protection
−36 °C (−33 °F)
−51 °C (−60 °F)