C175-16 Locomotive Engine Caterpillar

Aftercooler Coolant Temperature Is High

Usage:

Use this procedure to troubleshoot a high aftercooler coolant temperature. Also, use this procedure if one of the following event codes is active or logged.

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Table 1
J1939 Code and Description	CDL Code and Description	Comments
52-0 Engine Intercooler Temperature : High - most severe (3)	E771 (3) High Aftercooler Temperature	The ECM may shut down the engine. The code is logged.
52-15 Engine Intercooler Temperature : High - least severe (1)	E771 (1) High Aftercooler Temperature	The code is logged.
52-16 Engine Intercooler Temperature : High - moderate severity (2)	E771 (2) High Aftercooler Temperature	The ECM may derate the engine. The code is logged.

If the engine is shut down due to a high aftercooler temperature, cycle power to the engine ECM to restart the engine.

Probable Causes

Codes
Coolant level
Radiator
Leaks
Piping
Cooling fan
Relief valve
Water pump

Recommended Actions

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Table 2
Troubleshooting Test Steps	Values	Results
1. Check for Codes A. Connect Cat^® Electronic Technician (ET) to the service tool connector. B. Look for active codes that are associated with the system for the event code.	Codes	Result: An associated code is active. Repair: Troubleshoot any associated codes before continuing with this test. Result: A code is active or logged. Proceed to Test Step 2.
2. Check the Coolant Level for the Separate Circuit Aftercooler (SCAC) System	Coolant Level	Result: The coolant level is OK. Proceed to Test Step 3. Result: The coolant level is NOT OK. Repair: Add coolant. Check for leaks. If the problem is not resolved, proceed to Test Step 3.
3. Inspect the Radiator for the SCAC System A. Check the radiator fins for dirt, debris, and/or damage. B. Check for restrictions and internal blockage. C. 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 is dependent on the ambient temperature.	Radiator	Result: The radiator fins are not damaged and the radiator does not have a blockage. Proceed to Test Step 4. Result: The radiator fins are damaged and/or there is a blockage. Repair: Remove any dirt or debris, straighten any bent fins, and remove any blockage. If the problem is not resolved, proceed to Test Step 4.
4. Check for Air Leaks into the SCAC System A. Inspect the cooling system for leakage. Refer to Testing and Adjusting, "Cooling System - Test" for additional information.	Leaks	Result: There is not any leakage. Proceed to Test Step 5. Result: There is leakage. Repair: Repair any leaks immediately. If the problem is not resolved, proceed to Test Step 5.
5. Inspect the SCAC Piping A. Perform a visual inspection of the piping for the SCAC system. Look for piping that is damaged, crushed, or bent.	Piping	Result: The piping is OK. Proceed to Test Step 6. Result: The piping is NOT OK. Repair: Repair or replace any damaged piping. If the problem is not resolved, proceed to Test Step 6.
6. Check for Proper Operation of the Cooling Fan	Cooling Fan	Result: The cooling fan is operating correctly. Proceed to Test Step 7. Result: The cooling fan is not operating correctly. Repair: Repair or replace the cooling fan. If the problem is not resolved, proceed to Test Step 7.
7. Inspect the Pressure Relief Valve A. If the SCAC system is pressurized, pressure-test the SCAC system. Refer to Testing and Adjusting, "Testing the Cooling System" for additional information. B. Check that the seating surfaces of the pressure relief valve and the radiator cap are clean and undamaged.	Relief Valve	Result: The pressure relief valve and the radiator cap are operating correctly. Proceed to Test Step 8. Result: The pressure relief valve or the radiator cap is not operating correctly. Repair: Clean or replace damaged pressure relief valve or the radiator cap. If the problem is not resolved, proceed to Test Step 8.
8. Inspect the Water Pump A. Inspect the impeller of the water pump for damage or erosion. B. Ensure that the drive gear is not loose on the drive shaft of the water pump.	Water Pump	Result: There was a problem with the water pump. Repair: Repair or replace damaged water pump components. Verify that the repair eliminated the problem.

If the procedure did not correct the issue, contact your Cat dealer Technical Communicator (TC). For further assistance, your TC can confer with the Dealer Solutions Network (DSN).