Probable Causes
- Parameters
- Coolant level
- Combustion gases in the cooling system
- Water temperature regulators
- Restriction in the cooling system
- Coolant temperature gauge
- Water pump
- Excessive load on the system
Recommended Actions
Parameters
Verify that the values for the programmable monitoring system are correct. Refer to Troubleshooting, "System Configuration Parameters".
Coolant Level
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Pressurized System: Hot coolant can cause serious burns. To open the cooling system filler cap, stop the engine and wait until the cooling system components are cool. Loosen the cooling system pressure cap slowly in order to relieve the pressure. |
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Note: Low coolant level can be the result of overheating rather than the cause.
Check the coolant level.
Run the engine to operating temperature.
Inspect the cooling system for leaks. Check for the presence of coolant in the engine oil. This would indicate an internal coolant leak.
Determine whether the leak occurs before the engine overheats.
Add coolant, if necessary. If leaking is found, make the necessary repairs.
Combustion Gases in the Cooling System
Inspect the coolant for presence of bubbles. If bubbles are present, combustion gases may be entering the cooling system.
Water Temperature Regulators
Check the water temperature regulators for proper operation. Refer to Systems Operation/Testing and Adjusting.
Replace the water temperature regulators, if necessary.
Restriction in the Cooling System
The following cooling systems may not be operating properly.
- Raw water circuit for the heat exchanger
- Keel cooler
Raw Water Circuit for the Heat Exchanger
- Visually inspect the circuit for collapsed hoses and/or other restrictions.
- Clean the circuit and make the necessary repairs to the circuit.
Coolant Temperature Gauge
Compare the reading for the coolant temperature from the Caterpillar Electronic Technician (ET) to the reading for the coolant temperature from a mechanical gauge. The temperature should rise steadily as the engine is warmed. Ensure that the temperature is reasonable. Refer to Systems Operation/Testing and Adjusting.
If the reading on Cat ET for the coolant temperature is not reasonable, troubleshoot the circuit and the coolant temperature sensor. Refer to the diagnostic functional test Troubleshooting, "Engine Temperature Sensor Open or Short Circuit - Test".
Water Pump
Inspect the water pump impeller for damage and/or erosion. If necessary, repair the water pump or replace the water pump.
Excessive Load on the System
Reduce the load and verify that the condition does not reoccur.