GUIDE 2482987 - Caterpillar

Probable Causes
Low coolant level
Problem with the water pump
Restriction through the aftercooler
Insufficient flow of coolant
Buildup of scale in the cooling systemRecommended Actions
Check the Coolant Level and Inspect the Cooling System for Leaks
Check coolant level. If the coolant level is low, inspect the cooling system for leaks.If the coolant level is low, fill the cooling system. If leaks are found, make the necessary repairs.Water Pump
Remove the water pump for inspection. Refer to Disassembly and Assembly, "Water Pump - Remove". Repair the water pump, if necessary.Aftercooler
If the flow of coolant through the aftercooler is restricted, clean the aftercooler core.Check the Flow of Coolant
Use Caterpillar Electronic Technician (ET) in order to observe the pressure of the jacket water outlet when the engine is not running. Then observe the reading during engine operation.If the reading is not reasonable or if the reading is not within specifications, install a pressure gauge near the pressure sensor at the jacket water outlet. Compare the gauge reading with the reading from Cat ET.If the readings from the comparative gauge do not agree approximately with Cat ET, replace the pressure sensor.If the readings from the comparative gauge agree approximately with Cat ET, check the following components:
Check the water temperature regulators for proper operation.
Check for plugging of the radiator or of the heat exchanger.
Inspect the water pump for damage to the impeller.Make the necessary repairs.Scale Buildup
Drain the cooling system. Clean the cooling system. Fill the cooling system with new coolant. Maintain the cooling system properly. For instructions, refer to the engine's Operation and Maintenance Manual, "Cooling System Coolant (DEAC) - Change".