Cooling System Malfunctions - Diagnosis - Dodge D250 1990 Service Manual

Cooling System
DODGE Turbo Diesel
Cooling System Malfunctions - Diagnosis
Page 7-3
Cooling System Malfunctions - Diagnosis
The function of the coolant system is to maintain a specified
operating temperature for the engine. Some of the heat
generated by the engine is absorbed by the coolant flowing
through the passages in the cylinder block and head. Then,
heat Is removed from the coolant as it flows through the
radiator. When you troubleshoot overheating, remember that
too much oil in the oil pan can cause additional heat from
friction when the rod journals are submerged in oil.
Overfilling the engine with oil raises the oil temperature. This
additional heat is transferred to the coolant system at the oil
cooler.
The system is designed to use a specific quantity of coolant. If
the coolant level Is low, the engine will run hot.
Note: The engine or system has a leak if frequent addition of
coolant is necessary. Find and repair the leak.
Caution: The engine coolant p a s s a g e s must be
completely filled with coolant.
During operation entrapped air mixes with the coolant which
results in cavitation corrosion and poor heat transfer. Highly
aerated coolant can cause localized overheating of the cylinder
head and block which can result in a cracked head, scored
cylinder or blown head gasket.