COTTER 3B5315 - Caterpillar

Probable Causes
Low coolant level and/or coolant leakage
Water temperature regulator and/or pressure relief valve
Radiator or heat exchanger
Engine cooling fan (if equipped)
Coolant pump
Coolant temperature sensorRecommended Actions
Coolant
Inspect the coolant level. If necessary, add coolant.
Check for the correct mixture of antifreeze and water. Refer to Operation and Maintenance Manual.
Check the cooling system for leaks. Repair any leaks immediately.
Check for air in the cooling system. Refer to Systems Operation/Testing and Adjusting for the correct procedure.Water Temperature Regulator and/or Pressure Relief Valve
Pressure test the cooling system. Refer to Systems Operation/Testing and Adjusting for the correct procedure.
Check that the seating surfaces of the pressure relief valve and the radiator cap are clean and undamaged.
Check operation of the pressure relief valve and/or the water temperature regulator. If necessary, clean the components and/or replace the components.Radiator or Heat Exchanger
Radiator
Check the radiator fins for dirt, debris, and/or damage. Remove any dirt and/or debris and straighten any bent fins. Check for collapsed hoses and/or other restrictions.
Check the radiator for internal blockage. Refer to Systems Operation/Testing and Adjusting for more information.Heat Exchanger
Check for sufficient flow and temperature of the cooling water through the heat exchanger. If the flow of cooling water through the heat exchanger is insufficient, determine the location of the obstruction. If the temperature of the cooling water is too high, determine the cause. Make the necessary repairs.Faulty Engine Cooling Fan (if equipped)
If the fan is belt driven, check for loose drive belts. A loose fan drive belt will cause a reduction in the air flow across the radiator. Check the fan drive belt for proper belt tension. Adjust the tension of the fan drive belt, if necessary. Refer to Operation and Maintenance Manual.
Check the fan clutch, if equipped. A fan clutch or a hydraulic driven fan that is not turning at the correct speed can cause improper air speed across the radiator core. The lack of proper air flow across the radiator core can cause the coolant not to cool to the proper temperature differential.Coolant Pump
Inspect the impeller of the coolant pump for damage and/or erosion.
Make sure that the drive gear is not loose on the drive shaft of the coolant pump.
If necessary, replace the coolant pump. Refer to Disassembly and Assembly for the correct procedure.Check the Coolant Temperature Sensor and/or the Circuit
Check the reading of the coolant temperature on Cat 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, "Sensor Signal (Analog, Active) - Test".