Dodge D250 1990 Service Manual page 93

Coding System Malfunctions - Diagnosis
Page 7-4
Cooling System
DODGE Turbo Diesel
During filling, air must be vented from the engine coolant
passages. The air vents through the "jiggle pin" openings to the
top radiator hose and out the fill opening.
Note: Adequate venting is provided for a fill rate of 14
liter/minute [3.5 U.S. gallon/minute].
Caution: Never u s e only water for engine coolant. In
tropical climates where antifreeze availability may be
limited, use a corrosion Inhibitor (Cummins Liquid DCA)
to protect the engine cooling system.
A mixture of 50% ethylene-glycol base antifreeze is required for
operation of the engine in temperature environments above
-37°C [-34°F]. A mixture of 40% water and 60% antifreeze is
recommended for temperatures below -37°C [-34°F].
Caution: The small holes In the head gasket are
especially susceptible to plugging.
Water will cause rust formation reducing the flow in the smaller
codant passages.
Caution: T h e s e holes are orifices and their size Is
critical. Do not enlarge the size of the orifices. To do so
will disturb the coolant flow and will not solve an
overheating problem.
] Also, water used as a coolant for even a relatively short period
can result in the cup plugs rusting through allowing the coolant
to leak.
Note: A sudden loss of coolant from a heavily loaded engine
can result in severe damage to the pistons and cylinder bore.