C9.3 Engines for Caterpillar Built Machines Coolant Temperature Is Low Caterpillar

Coolant Temperature Is Low

C9.3 Engines for Caterpillar Built Machines [KENR5393]

C9.3 Engines for Caterpillar Built Machines Coolant Temperature Is High

C9.3 Engines for Caterpillar Built Machines Engine Cranks but Does Not Start

COOLING SYSTEM

C9.3 Engines for Caterpillar Built Machines Coolant Level - Test

C9.3 Engines for Caterpillar Built Machines Coolant Contains Oil

C9.3 Engines for Caterpillar Built Machines Coolant Contains Fuel

C9.3 Engines for Caterpillar Built Machines Coolant Temperature Is High

C9.3 Engines for Caterpillar Built Machines Coolant Temperature Is Low

C9.3 Engines for Caterpillar Built Machines Oil Contains Coolant

Use this procedure in order to troubleshoot a low coolant temperature.

Probable Causes

Cooling Fan
Water Temperature Regulator
Auxiliary Coolant Heater (if equipped)
Faulty Coolant Temperature Sensor and/or Circuit

Recommended Actions

Note: The procedures have been listed in order of probability. Complete the procedures in order.

Show/hide table

Table 1
Troubleshooting Test Steps	Values	Results
1. Check the Cooling Fan A. A cooling fan that is operating incorrectly can cause overcooling. Refer to Troubleshooting, "Cooling Fan Is Always ON", if necessary.	Cooling Fan	Result: The cooling fan is NOT OK. Repair: Repair or replace the cooling fan. Result: The cooling fan is OK. Proceed to Test Step 2.
2. Check the Water Temperature Regulator A. A regulator that is stuck open can cause overcooling. Test the water temperature regulator according to Testing and Adjusting, "Water Temperature Regulator - Test". B. Make sure that the proper water temperature regulator is installed. Refer to the Specifications manual for the correct water temperature regulator.	Water Temperature Regulator	Result: The water temperature regulator is NOT OK. Repair: Repair or replace the water temperature regulator. Result: The water temperature regulator is OK. Proceed to Test Step 3.
3. Check the Auxiliary Coolant Heater A. A malfunctioning auxiliary coolant heater can cause low coolant temperature. B. Determine if the engine is equipped with an auxiliary coolant heater. Check the heater for proper operation.	Auxiliary Coolant Heater	Result: The auxiliary coolant heater is NOT OK. Repair: Repair or replace the auxiliary coolant heater. Result: The auxiliary coolant heater is OK. Proceed to Test Step 4.
4. Check the Coolant Temperature Sensor and/or Circuit A. Check the reading of the coolant temperature on the Cat ET. The temperature should rise steadily as the engine is warmed. Ensure that the temperature is reasonable. B. If the reading on Cat ET for the coolant temperature is not reasonable, troubleshoot the circuit and the coolant temperature sensor. Refer to Troubleshooting, "Sensor Signal (Analog, Passive) - Test".	Coolant Temperature Sensor	Result: The coolant temperature sensor is NOT OK. Repair: Replace the coolant temperature sensor. Result: The coolant temperature sensor is OK STOP