- Low coolant level
- Problem with the water pump
- Restriction through the aftercooler
- Restriction in the cooling passages
- Air in the system
- Coolant flow switch
- Buildup of scale in the cooling system
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.
Check the weep hole on the water pump for leakage. Leakage will indicate a faulty water pump. Remove the water pump for inspection. Refer to Disassembly and Assembly, "Water Pump - Remove". Replace the water pump, if necessary.
Check the inlet air temperature to the aftercooler. The temperature can be read through Cat ET. A high inlet air temperature could indicate a restriction in the aftercooler. If the flow of coolant through the aftercooler is restricted, clean the aftercooler core.
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.
Check for Proper Operation Of the Coolant Flow Switch
Check the coolant flow switch for proper operation. Refer to Troubleshooting, "Coolant Flow Switch".
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".