Operation and maintenance manual

QSB4.5 and QSB6.7 Troubleshooting Symptoms Charts
Section TS - Troubleshooting Symptoms Page TS-15
Coolant Temperature Above Normal - Sudden Overheat
Cause Correction
STEP 1
Coolant level is below specification
.............
Inspect the engine and cooling system for external
coolant leaks. Repair if necessary. Add coolant.
Refer to Section 3.
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
Air in the cooling system
.............
Inspect and vent the cooling system. Refer to
Section 7.
OK
Go To Next Step
STEP 4
Fan drive belt is broken
.............
Check the fan drive belt. Replace the belt, if
necessary. Refer to Section A.
OK
Go To Next Step
STEP 5
Radiator cap is not correct, is malfunctioning, or
has low-pressure rating
.............
Check the radiator pressure cap. Refer to the OEM
service manual.
OK
Go To Next Step
STEP 6
Cooling system hose is collapsed, restricted, or
leaking
............. Inspect the hoses. Refer to Section 4.
OK
Go To Next Step
STEP 7
Coolant temperature gauge is malfunctioning
.............
Test the temperature gauge. Repair or replace the
gauge, if necessary.
OK
Go To Next Step
STEP 8
Charge air cooler fins, radiator fins, or air
conditioner condenser fins are damaged or
obstructed with debris
.............
Inspect the charge air cooler, air conditioner
condenser, and radiator fins. Clean, if necessary.
Refer to Section 4 and the OEM service manual.
OK
Go To Next Step
STEP 9
Cold weather radiator cover or winterfront is closed
.............
Open the cold weather radiator cover or the
winterfront. Maintain a minimum of 387 cm
2
[60
in
2
] of opening at all times. Refer to Section 1.
OK
Go To Next Step