3516B and 3516C Engines For MT4400D AC Off-Highway Trucks Caterpillar

Aftercooler Coolant Temperature Is High

Usage:

Use this procedure in order to troubleshoot a high aftercooler coolant temperature. Or, use this procedure if one of the following event codes is active.

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Table 1
Event Codes
Code and Description	Conditions which Generate this Code	System Response
52-15 Engine Intercooler Temperature : High - least severe (1)	The aftercooler coolant temperature is above the trip point temperature for the programmed delay time.	The code is logged. The ECM may derate the engine or shutdown the engine.
E771(1) High Aftercooler Temperature - least severe

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

Probable Causes

Codes
Coolant level for the Separate Circuit Aftercooler system (SCAC)
SCAC radiator
Leakage in the SCAC system
Piping for the SCAC system
Cooling fan for the SCAC system
Pressure relief valve
SCAC temperature regulator
SCAC water pump

Recommended Actions

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

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Table 2
Troubleshooting Test Steps	Values	Results
1. Active Codes and Logged Codes A.Establish communication between Caterpillar Electronic Technician (ET) and the Electronic Control Module (ECM). B. Monitor the diagnostic codes on Cat ET. Check for active or logged diagnostic codes. Specifically check for codes that could be associated to high aftercooler temperature. Refer to the histogram information for engine derates in Cat ET. Note: Wait at least 30 seconds in order for diagnostic codes to become active.	Engine Logged or Active Codes	Result: A diagnostic code is present. Repair:Troubleshoot any codes before continuing with this procedure. Reset the histogram. Verify that the repair eliminated the problem. Result: A diagnostic code is not present. Proceed to Test Step 2.
2. Coolant level for the SCAC A. Inspect the coolant level.	Coolant level	Result: The coolant level is OK. Proceed to Test Step 3. Result: The coolant level is OK. Repair:Add coolant. Verify that the repair eliminated the problem.
3. Radiator A.. Check the radiator fins for dirt, debris, and/or damage. B.Check for restrictions and internal blockage.	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 and/or debris, straighten any bent fins and remove any blockage. Verify that the repair eliminated the problem.
4. Leakage in the SCAC System A. Inspect the coolant for presence of bubbles. Cavitation will reduce the efficiency of the cooling system. Check the cooling system for combustion gases and inspect the cylinder liners for cracks.	Leakage	Result There is no leakage and the cylinder liners are OK. Proceed to Test Step 5. Result There is leakage and/or the cylinder liners are damaged. Repair:Repair any leaks immediately. Replace any damaged cylinder liners. Verify that the repair eliminated the problem.
5. Damage to 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. Verify that the repair eliminated the problem.
6. Faulty Cooling Fan A. Check for proper operation of the cooling fan.	Fan	Result The cooling fan is operating correctly. Proceed to Test Step 7. Result The cooling fan is not operating correctly. Repair:Repair the cooling fan. Verify that the repair eliminated the problem.
7.Pressure Relief Valve A.If the SCAC system is pressurized, check the operation of the pressure relief valve and the radiator cap for the SCAC radiator. B. Make sure that the drive gear is not loose on the drive shaft of the coolant pump.	Pressure relief valve	Result The pressure relief valve and the radiator cap are operating correctly. Proceed to Test Step 8. Result The pressure relief valve and/or the radiator cap are operating correctly. Repair:If necessary, clean the pressure relief valve and/or the radiator cap. Check that the seating surface of the valve is clean and undamaged. If necessary, install new parts. Verify that the repair eliminated the problem.
8. SCAC Temperature Regulators A. Check the operation of the SCAC temperature regulators. Refer to Specifications, "Water Temperature Regulator" for additional information.	Temperature Regulators	Result: The SCAC temperature regulators operate correctly. Proceed to Test Step 9. Result: There is a problem with the SCAC temperature regulators. Repair: Replace the regulators. Verify that the repair eliminated the problem.
9. Water Pump A. Inspect the impeller vanes of the water pump for damage and/or for erosion.	Water pump	Result There was a problem with the impeller vanes. Repair impeller vanes. Replace parts, if necessary. 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).