C7.1 Engines and Generator Sets Caterpillar

Use this procedure to troubleshoot high coolant temperature or use this procedure if one of the following event codes is active. Refer to Troubleshooting, "Event Codes" for information about event codes. Use the electronic service tool to view the current trip points for these codes.

Table 1

Diagnostic Trouble Codes for High Coolant Temperature
J1939 Code	CDL Code	Code Description (code descriptions may vary)	Comments
110-15	E361 (1)	Engine Coolant Temperature : High - least severe	The coolant temperature has been at 109° C (228° F) for 10 seconds. The ECM has been powered for at least 2 seconds. The engine has been running for at least 185 seconds. There are no electrical faults or battery faults on the circuit.
110-16	E361 (2)	Engine Coolant Temperature : High - moderate severity	The coolant temperature has been at 111° C (232° F) for 10 seconds. The ECM has been powered for at least 2 seconds. The engine has been running for at least 185 seconds. There are no electrical faults or battery faults on the circuit. The engine will be derated.
110-0	E361 (3)	Engine Coolant Temperature : High - most severe	The coolant temperature has been at 114° C (237° F) for 10 seconds. The ECM has been powered for at least 2 seconds. The engine has been running for at least 185 seconds. There are no electrical faults or battery faults on the circuit. The engine will be derated. The engine may stop.

Probable Causes

• Diagnostic codes

• Coolant level

• Coolant temperature sensor

• Radiator and hoses

• Radiator cap and pressure relief valve

• Water temperature regulator

• Engine cooling fan

• Quality of coolant

• Coolant pump

• NRS cooler

• Cylinder head gasket

Recommended Actions

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

Table 2

Troubleshooting Test Steps	Values	Results
1. Diagnostic Codes A. Use the electronic service tool to check for diagnostic codes that relate to the temperature in the cooling system.	Diagnostic Codes	Result: Diagnostic codes are not present. Return the unit to service. Result: Diagnostic codes are present. Proceed to Test Step 2.
2. Coolant Level A. Check the coolant level.	Engine coolant level	Result: The engine coolant level is low. Repair: Check the cooling system for leaks. Refer to Troubleshooting, "Coolant Level is Low" for additional information. Repair any leaks immediately. Result: The engine coolant level is OK. Proceed to Test Step 3.
3. Coolant Temperature Sensor A. Compare the reading for the coolant temperature on the electronic service tool to the reading for the coolant temperature on a calibrated test gauge.	Coolant temperature sensor	Result: The temperature sensor is not accurate. Repair: Troubleshoot the circuit and the coolant temperature sensor. Refer to Troubleshooting, "Sensor Signal (Analog, Passive) - Test". Result: The temperature sensor is reading accurately. Proceed to Test Step 4.
4. Radiator and Hoses A. Check the radiator fins for dirt, debris, and/or damage. B. Check for collapsed hoses and/or other restrictions. C. Check the radiator for internal blockage. Ensure that the radiator size is sufficient. An undersized radiator does not have enough area for the effective release of heat. An undersized radiator may cause the engine to run at a temperature that is higher than normal. The normal temperature depends on the ambient temperature.	Radiator and hoses	Result: The radiator fins are blocked or damaged. Repair: Remove any dirt and/or debris and straighten any bent fins. Result: The radiator has internal blockage. Repair: Remove the blockage. Result: The radiator fins are not damaged and the radiator does not have an internal blockage. Proceed to Test Step 5.
5. Radiator Cap and Pressure Relief Valve A. Pressure-test the cooling system. Refer to Systems Operation, Testing, and Adjusting, "Cooling System" for the correct procedure. B. Check that the seating surfaces of the pressure relief valve and the radiator cap are clean and undamaged. C. Check operation of the pressure relief valve and/or the water temperature regulator.	Radiator cap	Result: The pressure relief valve and/or the water temperature regulator are not operating correctly. Repair: Clean the components or replace the components. Result: The pressure relief valve and/or the water temperature regulator are operating correctly. Proceed to Test Step 6.
6. Water Temperature Regulator A. Check the water temperature regulator for correct operation. Refer to Systems Operation, Testing, and Adjusting, "Cooling System" for the proper procedure.	Water Temperature Regulator	Result: The water temperature regulator is not operating correctly. Repair: Replace the water temperature regulator. Refer to Disassembly and Assembly, "Water Temperature Regulator - Remove and Install". Result: The water temperature regulator is operating correctly. Proceed to Test Step 7.
7. Engine Cooling Fan A. Check that the cooling fan is operating correctly. B. Check the engine cooling fan for damage.	Fan	Result: The cooling fan is not operating correctly. Repair: Make sure that the cooling fan is being driven correctly. Make sure that the belt tensioner is operating correctly Result: The fan is damaged. Repair: Repair the fan or replace the fan, as necessary. Refer to Disassembly and Assembly, "Fan - Remove and Install". Result: The fan is OK. Proceed to Test Step 8.
8. Quality of Coolant A. Check the quality of the coolant. Refer to the Operation and Maintenance Manual, "Refill Capacities and Recommendations - Coolant".	Coolant	Result: The coolant is not of an acceptable quality. Repair: Drain and refill the coolant system with coolant of the correct quality. Refer to the Operation and Maintenance Manual, "Refill Capacities and Recommendations - Coolant". Result: The coolant is of an acceptable quality. Proceed to Test Step 9.
9. Inspection of the Coolant Pump A. Inspect the impeller of the coolant pump for damage and/or erosion. B. Make sure that the drive gear is not loose on the drive shaft of the coolant pump.	Coolant pump	Result The coolant pump is damaged or not operating correctly. Repair: If necessary, replace the coolant pump. Refer to Disassembly and Assembly, "Water Pump - Remove" and Disassembly and Assembly, "Water Pump - Install". Result The coolant pump is not damaged and the pump is operating correctly. Proceed to Test Step 10.
10. NRS Cooler A. Switch off the engine and allow the engine to cool to below normal working temperature. Remove the pressure cap for the coolant system. Perform a leak test on the cooling system and the NRS cooler. Refer to Systems Operation, Testing, and Adjusting, "Cooling System - Test". Refer to the subsection "Testing The Radiator And Cooling System For Leaks".	NRS cooler	Result: The leak test fails. Repair: Check the NRS cooler. Perform a leak test on the NRS cooler. Refer to Systems Operation, Testing, and Adjusting, "Exhaust Cooler (NRS) - Test". If necessary, install a replacement NRS cooler. Confirm that the fault has been eliminated. Result: The leak test is passed. Proceed to Test Step 11.
11. Cylinder Head Gasket A. Switch off the engine and allow the engine to cool to below normal working temperature. Remove the pressure cap for the coolant system. Perform a leak test on the cooling system and the NRS cooler. Refer to Systems Operation, Testing, and Adjusting, "Cooling System - Test". Refer to the subsection "Testing The Radiator And Cooling System For Leaks".	Cylinder Head gasket	Result: The leak test fails. Repair: Check the cylinder head gasket. Refer to the recommended action for the cylinder head gasket within Troubleshooting, "Oil Contains Coolant". Check the cylinder head for flatness. Refer to the recommended action for checking flatness of the cylinder head within Systems Operation, Testing, and Adjusting, "Cylinder Head - Inspect". Result: The leak test is passed. Contact the Dealer Solutions Network (DSN).