Recent Service Or Accident Repair:
WARNING: This page is about a different variant/trim than selected.
Determine if any recent service has been performed on vehicle that may affect the cooling system. This may be:
- Engine adjustments (incorrect timing)
- Slipping engine accessory drive belt(s)
- Brakes (possibly dragging)
- Changed parts. Incorrect water pump or pump rotating in wrong direction due to belt not correctly routed
- Reconditioned radiator or cooling system refilling (possibly under filled or air trapped in system).
- Service to electrically controlled viscous fan clutch
NOTE:
If investigation reveals none of the previous items as a cause for an engine overheating complaint, refer to COOLING SYSTEM DIAGNOSIS CHART .
These charts are to be used as a quick-reference only.
COOLING SYSTEM DIAGNOSIS CHART
| CONDITION | POSSIBLE CAUSES | CORRECTION |
|---|---|---|
| TEMPERATURE GAUGE READS LOW
NOTE:
Information on dash cluster is displayed based on broadcast data from PCM. DTC will be set for engine sensor circuit issues. |
1. Vehicle is equipped with a heavy duty cooling system. | 1. None. System operating normally. |
| 2. Thermostat stuck open | 2. Inspect and test thermostat. Refer to THERMOSTAT, DIAGNOSIS AND TESTING . | |
| 3. Coolant level low. | 3. Fill cooling system. Refer to STANDARD PROCEDURE . | |
| 4. Temperature gauge not functioning correctly. | 4. Check cluster. Refer to DIAGNOSIS AND TESTING . | |
| 5. Engine sensor stuck in range | 5. Monitor sensor with scan tool to verify sensor reading changes with increasing temperature. | |
| 6. Engine sensor failed out of range. | 6. A DTC will be set. | |
| 7. Electronically Controlled Viscous Fan Drive/mechanical viscous fan not operating properly. | 7. Check Electronically Controlled Viscous Fan Drive. | |
| TEMPERATURE GAUGE READS HIGH. COOLANT MAY OR MAY NOT BE LEAKING FROM SYSTEM
NOTE:
Temperature information displayed on dash cluster and EVIC are based on broadcast data from PCM. If engine temperatures exceed thresholds, power is reduced and a message of 'Oil Temp High - Speed May be Reduced' is displayed on the EVIC.
NOTE:
Beginning in MY2010, a 200 F thermostat is used in the Ram 2500 / 3500 pickup with the Cummins Turbo Diesel. It is normal for the coolant temperature gauge to read higher than in previous model years. |
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. Electronically-controlled viscous fan clutch not functioning correctly. | 2. Troubleshoot and if necessary repair the electronic viscous fan clutch. | |
| 3. Temperature gauge not functioning correctly. | 3. Check cluster. Refer to DIAGNOSIS AND TESTING . | |
| 4. Air trapped in cooling system | 4. Drain and refill cooling system. Refer to STANDARD PROCEDURE . | |
| 5. Radiator cap faulty. | 5. Replace radiator cap. | |
| 6. Plugged A/C or radiator cooling fins. | 6. Clean all debris away from A/C and radiator cooling fins. | |
| 7. Coolant mixture incorrect. | 7. Drain cooling system and refill with correct mixture. Refer to STANDARD PROCEDURE . | |
| 8. Thermostat stuck shut. | 8. Inspect and test thermostat. Refer to THERMOSTAT, DIAGNOSIS AND TESTING . | |
| 9. Bug screen or winter front being used. | 9. Remove bug screen or winter front. | |
| 10. Electronically controlled viscous fan drive not operating properly. | 10. Check viscous fan. | |
| 11. Cylinder head gasket leaking. | 11. Check for leaking head gaskets. Refer to DIAGNOSIS AND TESTING . | |
| 12. Heater core leaking. | 12. Replace heater core. Refer to CORE, HEATER, REMOVAL . | |
| 13. Cooling system hoses leaking. | 13. Tighten clamps or Replace hoses. | |
| 14. Brakes dragging. | 14. Check brakes. Refer to DIAGNOSIS AND TESTING . . | |
| 15. Accessory drive belt. | 15. Inspect and replace as necessary. Refer to BELT, SERPENTINE, DIAGNOSIS AND TESTING . | |
| 16. Water Pump. | 16. Inspect and replace as necessary. | |
| 17. Engine sensor stuck in range. | 17. Monitor sensor with scan tool to verify sensor reading changes increase in temperature. | |
| 18. Temperature sensor failed - Too High | 18. Clear the existing overheat fault. Drive the vehicle until thermostat opens. Verify that fault code does not return and coolant does not reach threshold of 230 degrees F. | |
| TEMPERATURE GAUGE READING INCONSISTENT (ERRATIC, CYCLES OR FLUCTUATES)
NOTE:
Information on dash cluster is displayed based on broadcast data from PCM. DTC will be set for engine sensor circuit issues. |
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 sensor defective. | 2. Check cluster or engine coolant temp sensor. Refer to 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 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. Refer to RADIATOR, ENGINE COOLING, INSTALLATION . | |
| 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. Electronically controlled viscous fan drive/mechanical viscous fan. | 2. None. Normal condition. | |
| 3. Fan blades striking surrounding objects. | 3. Locate contact point and repair as necessary. | |
| 4. Electronically controlled viscous fan drive/mechanical viscous fan bearing concern. | 4. Check viscous fan drive. | |
| 5. Electronically controlled viscous fan/mechanical viscous fan stuck on. | 5. Check viscous fan drive. | |
| 6. Obstructed air flow through radiator. | 6. 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. Electronically controlled viscous fan drive/ /mechanical viscous fan not working. | 2. Check viscous 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. Electronically controlled viscous fan/ /mechanical viscous fan stuck on. | Check viscous fan drive. | |
| 4. Water pump damaged. | 4. Replace water pump. | |
| HEAT ODOR | 1. Damaged or missing exhaust system heat shields. | 1. Repair or replace damaged or missing exhaust system heat shields. Refer to SHIELD, HEAT, DESCRIPTION . |
| 2. Electronically controlled viscous fan drive//mechanical viscous fan damaged. | 2. Check viscous fan drive. |