- High engine oil temperature or low engine coolant temperature
- Faulty temperature sensor and/or circuit
- Faulty water temperature regulators
Check the Engine Oil Temperature and the Engine Coolant Temperature
Use the Caterpillar Electronic Technician (ET) to check the temperature of the engine oil and the engine coolant.
If the engine oil temperature is high, refer to Troubleshooting, "Engine Oil Temperature (High)".
If the temperature of the engine coolant is low, refer to Troubleshooting, "Engine Coolant Temperature (Low)".
Check the Temperature Sensors and/or Circuits
Use a separate device to measure the temperatures of the engine oil and the engine coolant. Compare the measured temperatures to the readings on Cat ET.
If one or both of the readings are incorrect, troubleshoot the circuit(s). Refer to Troubleshooting, "Analog Sensor Signal".
Check the Water Temperature Regulators
The water temperature regulators should not begin to open until jacket water reaches opening temperature for the regulators. Allow the engine to cool and then start the engine. Check the tube at the outlet for the jacket water. If the tube is warm and normal operating temperature is not achieved yet, a regulator may be stuck open.
Check the water temperature regulators according to Systems Operation/Testing and Adjusting, "Testing the Cooling System". Replace the water temperature regulators, if necessary.