3Com Caterpillar Commercial Diesel Engine SEBU6251-06 - Manual (Page 33)

33
Maintenance Section
Cooling System Specifications
When a heavy-duty coolant/antifreeze is used,
treat the cooling system with three to six
percent Caterpillar SCA by volume. For more
information, see this publication, “Conventional
Coolant/Antifreeze Cooling System Maintenance”
topic (Maintenance Section).
If Caterpillar SCA is not used, select a commercial
SCA. The commercial SCA must provide a minimum
of 1200 mg/L or 1200 ppm (70 grains/US gal) of
nitrates in the final coolant mixture.
Coolant/antifreeze that meets “ASTM D5345” or
“ASTM D4985” specifications MAY require treatment
with SCA at the initial fill. These coolants WILL
require treatment with SCA on a maintenance basis.
When concentrated coolant/antifreeze is mixed,
Caterpillar recommends mixing the concentrate with
distilled water or with deionized water. If distilled
water or deionized water is not available, water
which has the required properties may be used. For
the water properties, see this publication, “General
Coolant Information” topic (Maintenance Section).
i01096747
Water/Supplemental Coolant
Additive (SCA)
SMCS Code: 1350; 1352; 1395
NOTICE
All Caterpillar diesel engines equipped with air-to-air
aftercooling (ATAAC) require a minimum of 30 percent
glycol to prevent water pump cavitation.
NOTICE
Never use water alone without Supplemental Coolant
Additives (SCA) or without inhibited coolant. Water
alone is corrosive at engine operating temperatures.
Water alone does not provide adequate protection
against boiling or freezing.
Note: Premix the coolant solution in order to provide
protection to the lowest ambient temperature that
is expected.
Note: Pure undiluted antifreeze freezes at
−
23

C
(
−
9

F).
In engine cooling systems that use Supplemental
Coolant Additive (SCA) and water alone, Caterpillar
recommends the use of SCA. SCA helps to prevent
the following conditions from occurring:
• Corrosion
• Formation of mineral deposits
• Cavitation erosion of the cylinder liner
• Foaming of the coolant
If Caterpillar SCA is not used, select a commercial
SCA. The commercial SCA must provide a minimum
of 2400 mg/L or 2400 ppm (140 grains/US gal) of
nitrates in the final coolant mixture.
The quality of the water is a very important factor
in this type of cooling system. Distilled water
or deionized water is recommended for use in
cooling systems. If distilled water or deionized
water is not available, use water that meets the
minimum requirements that are listed in the table for
recommended water properties in this publication,
“General Coolant Information” topic (Maintenance
Section).
A cooling system that uses a mixture of SCA
and water only needs more SCA than a cooling
system that uses a mixture of glycol and water. The
SCA concentration in a cooling system that uses
SCA and water should be six to eight percent by
volume. Refer to Table 22 for the amount of SCA
that is required for various capacities of the cooling
system.