elements, liquid and dry bulk inhibitor additives and as an
integral part of antifreeze.
Commercially packaged inhibitor systems are available
which can be added directly to the engine coolant or to
bulk storage tanks containing coolant solution. Both
chromate and non-chromate systems are available and
care should be taken regarding inhibitor compatibility
with other coolant constituents.
Non-chromate inhibitor systems are recommended for
use in Detroit Diesel engines. These systems can be
used with either water or water-and-antifreeze solutions
and provide corrosion protection, pH control and water
softening. Some non-chromate inhibitor systems offer
the additional advantage of a simple on-site test to
determine protection level. Since they are added directly
to the coolant, require no additional hardware or
Fig. 2 - Coolant Freezing and Boiling Temperatures vs.
All inhibitors become depleted through normal operation
Antifreeze Concentration (Sea Level)
and additional inhibitor must be added to the coolant at
prescribed intervals to maintain original strength levels.
These test strips are used to measure the freeze
Always follow the supplier's recommendations on
protection and/or inhibitor strength of ethylene glycol-
inhibitor usage and handling.
based antifreeze. To avoid a false reading caused by
variations in reserve alkalinity. Detroit Diesel Allison
suggests using test strips that measure depletable
Do not use one
inhibitor concentration directly.
Some chemical manufacturers have developed test
manufacturer's test strips to measure the chemical
strips for use with their antifreeze or coolant additives.
content of another's antifreeze and/or inhibitors. Always
follow the manufacturer's recommended test procedures.