36 SEBU8191-01
Maintenance Section
Refill Capacities
Additives
Additives help to protect the metal surfaces of
the cooling sy
stem. A lack of coolant additives or
insufficient amounts of additives enable the following
conditio ns to occur:
•
Corrosion
•
Formation o
f mineral deposits
•
Rust
•
Scale
•
Foaming of
the coolant
Many additives are depleted during engine operation.
These addi
tives must be replaced periodically.
Additives must be added at the correct concentration.
Overconc
entration of additives can cause the
inhibitors to drop out-of-solution. The deposits can
enable the following problems to occur:
•
Formation of gel compounds
•
Reducti
on 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
again
st the following conditions:
•
Boiling
•
Freezing
•
Cavi
tation of the water pump
For optimum performance, Perkins recommends a
1:1 m
ixture of a water/glycol solution.
Note: Use a mixture that will provide protection
aga
inst the lowest ambient temperature.
Note: 100 percent pure glycol will freeze at a
tem
perature of −13° C (8.6° F).
Most conventional coolants use ethylene glycol.
Pr
opylene glycol may also be used. In a 1:1 mixture
with water, ethylene and propylene glycol provide
similar protection against freezing and boiling. See
Ta
bles 14 and 15.
Table 14
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 the reduced heat
transfer capability of propylene glycol. Use ethylene
glycol in conditions that require additional protection
against boiling or freezing.
Table 15
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.
Coolant Recommendations
The following two coolants are used in Perkins diesel
engines:
Preferred – Perkins Extended Life Coolant (ELC)
Acceptable – A commercial heavy-duty coolant that
meets “ASTM D6210” specifications
NOTICE
Do not use a commercial coolant/antifreeze that on-
ly meets the ASTM D3306 specification. This type of
coolant/antifreeze is made for light automotive appli-
cations.
Perkins recommends a 1:1 mixture of water and
glycol. This mixture of water and glycol will provide
optimum heavy-duty performance as a coolant. This
ratio may be increased to 1:2 water to glycol if extra
freezing protection is required.
A mixture of Supplement Coolant Additive (SCA)
and water is acceptable. Perkins recommends
a six percent to eight percent concentration of
SCA in those cooling systems. Distilled water or
deionized water is preferred. Water which has the
recommended properties may be used.
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