3176C, 3406E and 3456 Industrial Engines Troubleshooting – Exhaust Temperature Is High

Use this procedure in order to troubleshoot a high exhaust temperature.

Probable Causes


  • Diagnostic codes 
  • Air inlet and exhaust system 
  • Fuel injectors 
  • Aftercooler (if applicable) 

Recommended Actions

Diagnostic Codes

Connect Caterpillar Electronic Technician (ET) and check for active and/or logged diagnostic codes. Troubleshoot any active diagnostic codes before continuing with this procedure.

Air Inlet and Exhaust System

Check for air inlet restrictions and/or leaks. A one degree increase in the inlet manifold temperature will increase the exhaust temperature by approximately three degrees. Check for leaks between the exhaust manifold and the turbocharger. Check for exhaust restrictions.

Fuel Injectors

Faulty injectors that deliver too much fuel will increase exhaust temperatures. Connect Cat ET in order to determine if any diagnostic codes for the injector solenoids are present. Perform the “Injector Solenoid Test”. Observe that the injector solenoids are being energized on Cat ET. Perform the “Cylinder Cutout Test”. Locate the misfiring cylinder. Refer to Troubleshooting, “Injector Solenoid – Test”.

Aftercooler (if applicable)

Normal intake manifold pressure with high exhaust temperature can be caused by blockage of the fins of the aftercooler core.

If the application has an aftercooler, check the aftercooler for correct operation. Check for blockage in the cores of the aftercooler.

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