| TEMPERATURE GAUGE READS LOW |
1. Vehicle is equipped with a heavy duty cooling system. |
1. None. System operating normally. |
| 2. Temperature gauge not connected |
2. Connect gauge. |
| 3. Temperature gauge connected but not operating. |
3. Check gauge. (Refer to ELECTRICAL/INSTRUMENT CLUSTER - DIAGNOSIS AND TESTING)
. |
| 4. Coolant level low. |
4. Fill cooling system. Refer to STANDARD PROCEDURE . |
| TEMPERATURE GAUGE READS HIGH. COOLANT MAY OR MAY NOT BE LEAKING FROM SYSTEM |
1. Vehicle overloaded, high ambient (outside) temperatures with A/C turned on, stop and go driving or prolonged operation at idle speeds. |
1. Temporary condition, repair not required. Notify customer of vehicle operation instructions located in Owners Manual. |
| 2. Temperature gauge not functioning correctly. |
2. Check gauge. (Refer to ELECTRICAL/INSTRUMENT CLUSTER - DIAGNOSIS AND TESTING)
. |
| 3. Air trapped in cooling |
3. Drain cooling system and refill. Refer to STANDARD PROCEDURE . |
| 4. Radiator cap faulty. |
4. Replace radiator cap. |
| 5. Plugged A/C or radiator cooling fins. |
5. Clean all debris away from A/C and radiator cooling fins. |
| 6. Coolant mixture incorrect. |
6. Drain cooling system and refill with correct mixture. Refer to STANDARD PROCEDURE . |
| 7. Thermostat stuck shut. |
7. Replace thermostat. |
| 8. Bug screen or winter front being used. |
8. Remove bug screen or winter front. |
| 9. Viscous fan drive not operating properly. |
9. Check viscous fan. |
| 10. Cylinder head gasket leaking. |
10. Check for leaking head gaskets. (Refer to COOLING - DIAGNOSIS AND TESTING) . |
| 11. Heater core leaking. |
11. Replace heater core. |
| 12. Cooling system hoses leaking. |
12. Tighten clamps or Replace hoses. |
| 13. Brakes dragging. |
13. Check brakes. Refer to BRAKES - BASE
. |
| TEMPERATURE GAUGE READING INCONSISTENT (ERRATIC, CYCLES OR FLUCTUATES) |
1. Heavy duty cooling system, extreme cold ambient (outside) temperature or heater blower motor in high position. |
1. None. System operating normally. |
| 2. Temperature gauge or gauge sensor defective. |
2. Check gauge. (Refer to ELECTRICAL/INSTRUMENT CLUSTER - DIAGNOSIS AND TESTING) |
| 3. Temporary heavy usage or load. |
3. None. Normal condition. |
| 4. Air trapped in cooling system. |
4. Fill cooling system. Refer to STANDARD PROCEDURE . |
| 5. Water pump |
5. Replace water pump. |
| 6. Air leak on suction side of water pump. |
6. Check for leak. (Refer to COOLING - DIAGNOSIS AND TESTING) . |
| RADIATOR CAP LEAKING STEAM AND/OR COOLANT INTO RESERVOIR BOTTLE. (TEMPERATURE GAUGE MAY READ HIGH) |
1. Radiator cap defective. |
1. Replace radiator cap. |
| 2. Radiator neck surface damaged. |
2. Replace radiator. |
| HOSE OR HOSES COLLAPSE WHEN ENGINE IS COOLING. |
1. Vacuum created in cooling system on engine cool-down is not being relieved through coolant reservoir/overflow system. |
1. Replace radiator cap, check vent hose between radiator and reservoir bottle for blockage also check reservoir bottle vent for blockage. |
| NOISY FAN |
1. Fan blade(s) loose, damaged. |
1. Replace fan blade assembly. |
| 2. Thermal viscous fan drive. |
2. None. Normal condition. |
| 3. Fan blades striking surrounding objects. |
3. Locate contact point and repair as necessary. |
| 4. Thermal viscous fan drive bearing. |
4. Replace viscous fan drive assembly. |
| 5. Obstructed air flow through radiator. |
5. Remove obstruction. |
| INADEQUATE AIR CONDITIONER PERFORMANCE (COOLING SYSTEM SUSPECTED) |
1. Radiator and/or A/C condenser air flow obstructed. |
1. Remove obstruction and/or clean. |
| 2. Thermal viscous fan drive not working. |
2. Check fan drive. |
| 3. Air seals around radiator damaged or missing. |
3. Inspect air seals, repair or replace as necessary. |
| INADEQUATE HEATER PERFORMANCE. GAUGE MAY OR MAY NOT READ LOW. |
1. Heavy duty cooling system, and cooler ambient temperatures. |
1. None. Normal condition. |
| 2. Obstruction in heater hoses. |
2. Remove hoses, remove obstruction. |
| 3. Water pump damaged. |
3. Replace water pump. |
| HEAT ODOR |
1. Damaged or missing drive line heat shields. |
1. Repair or replace damaged or missing heat shields. |
| 2. Thermal viscous fan drive damaged. |
2. Check thermal viscous fan drive. |