BOLT 9X8881 - Caterpillar

Probable Causes
High ambient air temperature
High coolant temperature
High inlet air restriction and/or high altitude
Faulty inlet air temperature sensor and/or circuit
Insufficient flow of cooling water through the aftercooler
Insufficient flow of air through the aftercoolerRecommended Repairs
High Ambient Air Temperature
Determine if the ambient air temperature is within the design specifications for the cooling system.Determine the cause of the high air temperature. Make corrections, when possible.Coolant Temperature
Refer to Troubleshooting, "Engine Coolant Temperature (High)".Check for High Inlet Air Restriction and/or High Altitude
The maximum allowable air inlet restriction is 3.75 kPa (15 inches of H2O). If the indication is higher than the maximum permissible restriction, clean the filter element or install a new filter element. Check the restriction again. If the restriction remains too high, inspect the air inlet piping before the air cleaner for obstructions.When inlet air pressure is low, the turbocharger works harder in order to achieve the desired inlet manifold pressure. This increases inlet air temperature.Inlet Air Restriction
Check for plugged air filters. Check for obstructions to the air inlet. Replace the air filters and/or remove the obstruction from the air inlet.High Altitude
Make sure that the settings for the engine are correct for the altitude.Check the Temperature Sensor and/or the Circuit
Allow the sensor to cool and remove the sensor. Check the reading for the inlet air temperature. If the sensor is OK, the reading and the ambient temperature are approximately equal.If the reading is not correct, switch the sensor with a sensor that is known to be good. Verify that the problem is solved.Check for Sufficient Flow of Cooling Water Through the Aftercooler
Check the inlet temperature of the coolant for the aftercooler. If the temperature is OK, check the outlet temperature of the coolant. A high temperature differential indicates an insufficient flow rate.If there is a high differential between the inlet temperature and the outlet temperature of the coolant for the aftercooler, perform the following procedures:
Check the water circuit of the aftercooler for obstructions.
Check the pump for proper operation.
Make repairs, if necessary.Check for Sufficient Flow of Air Through the Aftercooler
Determine the pressure differential of the inlet air across the aftercooler. For specific data, refer to the Technical Marketing Information for the engine.If the pressure differential of the air across the aftercooler does not match the specifications, clean the aftercooler.