- Faulty jacket water heater
- Faulty coolant temperature sensor and/or circuit
- Faulty water temperature regulators
Determine if the jacket water heaters are functioning properly.
If the jacket water heaters are not functioning properly, determine the cause of the malfunction of the heaters. Make the necessary repairs.
Check the Coolant Temperature Sensor and/or the Circuit
Check the reading of the coolant temperature with the Caterpillar Electronic Technician (ET). The temperature should rise steadily as the engine is warmed. Ensure that the temperature is reasonable.
If the reading on Cat ET for the coolant temperature is not reasonable, troubleshoot the circuit and the coolant temperature sensor. 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 hose at the outlet for the jacket water. If the hose is warm and normal operating temperature is not achieved yet, a regulator may be stuck open.
If the water temperature regulators are malfunctioning, check the water temperature regulators according to Systems Operation/Testing and Adjusting, "Testing the Cooling System". Replace the water temperature regulators, if necessary.