Cooling System Specifications
General Coolant Information
SMCS Code: 1350; 1395
Adding coolant to an overheated engine could result in
damage to the engine. Allow the engine to cool before
If the machine is to be stored in, or shipped to, an area
with freezing temperatures, the cooling system must be
protected to the lowest outside (ambient) temperature.
The engine cooling system is normally protected to -28°C
(-20° F) with Caterpillar Antifreeze, when shipped from the
factory unless special requirements are defined.
In cold weather, frequently check the specific gravity of
the coolant solution to ensure adequate protection.
Clean the cooling system for the following reasons:
contamination of the cooling system, engine overheating, and
foaming in the radiator.
Air pockets can form in the cooling system if the cooling
system is filled at a rate that is greater than 20 L (5 US gal) per
After you drain the cooling system and after you refill the
cooling system, operate the engine. Operate the engine
without the radiator cap until the coolant reaches normal
operating temperature and the coolant level stabilizes. Make
sure that the coolant is maintained to the proper level.
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 problems
can develop without water temperature regulators
For more detailed information, refer to the following
publications: Special Publication, SEBD0518, "Know Your
Cooling System" and Special Publication, SEBD0970, "Coolant
and Your Engine".
Many engine failures are related to the cooling system.
Cooling system failures include the following problems:
overheating, leakage of the water pump, plugged radiators,
and cylinder liner pitting. These failures could be avoided with
proper cooling system maintenance. Maintenance of the
engine coolant is important to the engine life and to the
performance. Maintaining the quality of the engine's coolant is
as important as maintaining the quality of the engine's fuel and
Coolant provides three main functions:
Coolant provides cooling by transferring heat from the
engine to the air.
Coolant provides corrosion protection.
Coolant provides anti-boil protection and antifreeze
Coolant is normally composed of three elements:
Never use water alone without Supplemental Coolant
Additive (SCA's) or inhibited coolant. Water alone is
corrosive at engine operating temperatures and does not
provide adequate boil protection.
Water is used to transfer the heat in the coolant solution. For
this reason, it is important to use water that meets the following
recommendations can interfere with the transfer of heat. This
water can also be corrosive.
Distilled water or deionized water is recommended for use in
cooling systems. Do not use hard water in engine cooling
systems. Also, never use water that has been softened with
salt. If distilled water or deionized water is not available, use
water that meets the minimum requirements that are listed in
the following table.
All Caterpillar diesel engines equipped with air-to-air
aftercooling (ATAAC) require a minimum of 30 percent
glycol to prevent water pump cavitation.
Cooling System Specifications