IMPORTANT: Check inhibitors between drain intervals
every 6 months or 30,000 miles at low
speed operation service interval or 12
months or 25,000 miles at normal
operation service interval. Replenish
inhibitors by the addition of a
supplemental coolant additive as
DO NOT use soluble oil.
Additives eventually lose their effectiveness and must be
recharged with additional supplemental coolant additives
available in the form of liquid coolant conditioner. See
TESTING DIESEL ENGINE COOLANT and
REPLENISHING SUPPLEMENTAL COOLANT
ADDITIVES (SCAs) BETWEEN COOLANT CHANGES, as
described later in this group.