Fuel, Oil and Coolant Specifications
plate will be attacked by solutions which will not be
detrimental to other metals in the cooling system. The
dissolved magnesium will be deposited in the hottest
zones of the engine where heat transfer is most critical
(Figure 3). The use of aluminum or zinc in preference
to magnesium is recommended to eliminate this type of
A high chloride coolant will have a detrimental effect on
the water softening capabilities of systems using ion-
Accumulations of calcium and
magnesium ions removed from the coolant and held
captive by the zeolite resin can be released into the
coolant by a regenerative process caused by high
chloride content solutions.
Bulk Inhibitor Additives
Commercially packaged inhibitor systems are available
which can be added directly to the engine coolant or to
bulk storage tanks containing coolant solution.
When freeze protection is required, an ethylene glycol
Both chromate and non-chromate systems are available
base permanent antifreeze should be used. An inhibitor
and care should be taken regarding inhibitor
system is included in this type of antifreeze and no
compatability with other coolant constituents (Figure 2).
additional inhibitors are required on initial fill if a
minimum antifreeze concentration of 30% by volume is
A non-chromate inhibitor system is recommended for
used. Solutions of less than 30% concentration do not
use in Detroit Diesel engines.
provide sufficient corrosion protection. Concentrations
systems can be used with either water or ethylene glycol
over 67% adversely affect freeze protection and heat
antifreeze solutions and provide corrosion protection, pH
transfer rates (Figure 4).
control and water softening. Some of the approved non-
chromate inhibitor systems offer the additional
Methoxy propanol base antifreeze may be used for
advantage of a simple on site test to determine
freeze protection in Series 53 engines. Before installing
protection level and, since they are added directly to the
methoxy propanol base antifreeze in an engine, the
coolant, require no additional hardware or plumbing.
entire cooling system should be drained, flushed with