TM 5-3820-245-14&P
cylinder walls, preventing normal heat transfer. An
ANTIFREEZE
abnormally low coolant level can cause the water pump
to become (: air-bound," a condition in which it works
When freeze protection is required, an antifreeze
feverishly but pumps nothing. Without proper heat
meeting GM specification 1899M must be used. An
transfer, silicone elastomer head-to-block water hole
inhibitor system is included in this type of antifreeze and
seals can deteriorate and cylinder components can
no additional inhibitors are required on initial fill if a
expand so that pistons rapidly cut through the lubricant
minimum antifreeze concentration of 30% by volume is
on the liner walls. Scuffing and piston seizure may
used. Solutions of less than 30% concentration do not
follow.
provide sufficient corrosion protection. Concentrations
over 67% adversely affect freeze protection and heat
CAUTION: Use extreme care when removing a
transfer rates (Fig. 2).
radiator pressure control cap from an engine.
Ethylene glycol base antifreeze is recommended for use
The sudden release of pressure from a heated
in all Detroit Diesel engines. Methyl alcohol base
cooling system can result in a loss of coolant
anitfreeze is not recommended because of its effect on
and possible personal injury (scalding) from the
the non-metallic components of the cooling system and
hot liquid.
because of its low boiling point. Methoxy propanol base
antifreeze is not recommended for use in Detroit Diesel
An engine may contain the correct amount of properly
engines due to the presence of fluoroelastomer seals in
inhibited coolant, but still fail to adequately cool the
the cooling system.
engine. In cases where this occurs, other causes of low
coolant flow, either engine or cooling system related,
Before installing ethylene glycol base antifreeze in a unit
should be investigated.
that has previously operated with methoxy propanol, the
entire cooling system should be drained, flushed with
1. Always use a properly inhibited coolant.
clean water, and examined for rust, scale contaminants,
etc. If deposits are present, the cooling system must be
2. Do not use soluble oil.
chemically cleaned with a commercial grade heavy-duty
descaler.
3. Maintain the prescribed inhibitor strength.
The inhibitors in antifreeze should be replenished at
4. Always follow the manufacturer's recommendations
approximately 500 hour intervals or by test with a non-
on inhibitor usage and handling.
chromate inhibitor system.
Commercially available
inhibitor systems may be used to reinhibit antifreeze
5. If freeze protection is required, use a solution of water
solutions.
and antifreeze meeting GM specification 1899M.
Sealer Additives
6.
Reinhibit antifreeze with
a
recommended
nonchromate inhibitor system.
Antifreeze with sealer additives is not recommended for
use in Detroit Diesel engines due to plugging possibilities
7. Do not use a chromate inhibitor with antifreeze.
throughout various areas of the cooling system, including
cooling system bleed holes and water pump drain holes.
8. Do not use methoxy propanol base antifreeze in
Detroit Diesel engines.
GENERAL RECOMMENDATIONS
9. Do not mix ethylene glycol base antifreeze with
All Detroit Diesel engines incorporate pressurized cooling
methoxy propanol base antifreeze in the cooling system.
systems which permit operation at temperatures higher
than non-pressurized systems. It is essential that these
10. Do not use antifreeze containing sealer additives.
systems be kept clean and leakfree, that filler caps and
pressure relief mechanisms be correctly installed at all
11. Do not use methyl alcohol base antifreeze.
times and that coolant levels be properly maintained.
12. Use extreme care when removing the radiator
Always maintain engine coolant at the proper level. A
pressure control cap.
low coolant level allows the water pump to mix air with
the coolant. Air bubbles in the coolant can "insulate" the
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