Dodge D250 1990 Service Manual page 161

Troubleshooting Logic
Page9A-22
Base Engine Components
DODGE Turbo Diesel
Coolant Temperature Above Normal (Continued)
Cause
Correction
Plugged Cooling Passages in Radiator, Flush the System and Fill with Clean
Head, Head Gasket or Block Coolant.
OK
Engine Overloaded Verify that the Engine Load Rating is
Not Being Exceeded.