Operation and maintenance manual

QSB4.5 and QSB6.7 Troubleshooting Symptoms Charts
Section TS - Troubleshooting Symptoms Page TS-17
Coolant Temperature Below Normal
Cause Correction
STEP 1
Coolant temperature gauge or sensor is
malfunctioning
.............
Test the gauge and the sensor. Repair or replace,
if necessary. Refer to OEM service manual.
OK
Go To Next Step
STEP 2
Electronic fault codes are active
.............
For instructions on how to read active fault codes,
refer to Section 1. If fault codes are active, contact
a Cummins Authorized Repair Facility.
OK
Go To Next Step
STEP 3
Engine is operating at low ambient temperature
.............
Check the winterfront, shutters, and under-the-
hood air. Use under-the-hood intake air in cold
weather. Refer to Cold Weather Operation, Bulletin
3387266, and Section 1.
OK
Go To Next Step
STEP 4
Fan drive or fan controls are malfunctioning
.............
Check the fan drive and controls. Refer to the
OEM service manual.
OK
Go To Next Step
STEP 5
Coolant temperature gauge is malfunctioning
.............
Test the temperature gauge. Repair or replace the
gauge, if necessary.
OK
Go To Next Step
STEP 6
Thermostat is not correct or is malfunctioning
.............
Check the thermostat for the correct part number
and for correct operation. Contact a Cummins
Authorized Repair Facility.
OK
Go To Next Step
STEP 7
Contact a Cummins® Authorized Repair Facility