Scan Tool Data List
| Scan Tool Parameter | Data List | Units Displayed | Typical Data Value |
|---|
| Ignition Switch in RUN/Engine running/Automatic Transmission in PARK/Manual Transmission in NEUTRAL/Air Conditioner is OFF |
| ECT Sensor | Engine Data 1, Engine Data 2, Engine Data 3 | °C/°F | Varies |
Powertrain Control Module
| IMPORTANT | Review the system operation in order to familiarize yourself with the system functions. Refer to Cooling System Description and Operation . |
Visual/Physical Inspection
- Inspect for aftermarket devices which could affect the operation of the Cooling System. Refer to «Checking Aftermarket Accessories»(ref-266894-S42790233922007100900000) .
- Inspect the easily accessible or visible system components for obvious damage or conditions which could cause the symptom.
Symptom List
Refer to a symptom diagnostic procedure from the following list in order to diagnose the symptom
- «Engine Overheating»(ref-266906-S38249236042007100900000)
- «Loss of Coolant»(ref-266906-S32305668182007100900000)
- «Thermostat Diagnosis»(ref-266906-S07544520382007100900000)
- «Coolant Heater Inoperative»(ref-266906-S24551150622007100900000)
- «Engine Fails To Reach Normal Operating Temperature»(ref-266906-S21807706072007100900000)
Diagnostic Aids
The engine may overheat due to an intermittent operation of the thermostat.
| Step | Action | Values | Yes | No |
|---|
| DEFINITION: Engine temperature lamp comes ON and stays ON or the temperature gage shows hot or coolant overflows from the coolant recovery reservoir onto the ground while the engine is running. |
| 1 | Did you perform the Diagnostic System Check - Vehicle? | | Go to Step 2 | Go to Diagnostic System Check - Vehicle |
| 2 | Inspect the coolant recovery reservoir for low coolant. Is there a loss of coolant? | | Go to Loss of Coolant | Go to Step 3 |
| 3 | IMPORTANT: Do not allow the engine temperature to exceed the specified value. Start the engine and allow to reach normal operating temperature.Does the engine begin to exceed the specified value? | 107°C (225°F) | Go to Step 4 | Go to Diagnostic Aids |
| 4 | Inspect for loose, damaged, and/or missing of the following: The A/C condenser seals The front air deflector The side seals Repair the system as necessary. Does the engine still overheat? | | Go to Step 5 | Go to Step 17 |
| 5 | Using the J 23688 Coolant and Battery Fluid Tester, test for insufficient coolant concentration. See Special Tools . Is the coolant protection greater than the specified value? | 37°C (-34°F) | Go to Step 6 | Go to Step 7 |
| 6 | Correct the coolant concentration as necessary. Does the engine still overheat? | | Go to Step 7 | Go to Step 17 |
| 7 | Inspect for obstructed radiator air flow or bent radiator fins. Is the radiator air flow obstructed? | | Go to Step 8 | Go to Step 9 |
| 8 | Clean the radiator. Refer to Radiator Cleaning . Does the engine still overheat? | | Go to Step 9 | Go to Step 17 |
| 9 | Inspect the drive belt tensioner. Refer to Drive Belt Tensioner Diagnosis . Is the drive belt tensioner working properly and is the tension correct? | | Go to Step 11 | Go to Step 10 |
| 10 | Replace the drive belt tensioner. Refer to Drive Belt Tensioner Replacement . Does the engine still overheat? | | Go to Step 11 | Go to Step 17 |
| 11 | Inspect the thermostat for proper operation. Refer to Thermostat Diagnosis . Does the thermostat operate properly? | | Go to Step 13 | Go to Step 12 |
| 12 | Replace the thermostat. Refer to Engine Coolant Thermostat Replacement . Does the engine still overheat? | | Go to Step 13 | Go to Step 17 |
| 13 | Inspect for an inoperative fan clutch. Refer to Fan Clutch Diagnosis . Does the engine still overheat? | | Go to Step 14 | Go to Step 17 |
| 14 | Inspect for blocked cooling system passages. Are the cooling system passages blocked? | | Go to Step 15 | Go to Step 16 |
| 15 | Replace the radiator. Refer to Radiator Replacement . Does the engine still overheat? | | Go to Step 16 | Go to Step 17 |
| 16 | Replace the engine water pump. Refer to Water Pump Replacement . Did you complete the repair? | | Go to Step 17 | |
| 17 | Operate the system in order to verify the repair. Did you correct the condition? | | System OK | Go to Step 2 |
| IMPORTANT |
|---|
| Do not allow the engine temperature to exceed the specified value. |
The engine may fail to reach normal operating temperature due to an intermittent operation of the thermostat.
| Step | Action | Yes | No |
|---|
| DEFINITION: Normal coolant temperature readings will be expected to vary from 92-107°C (198-225°F). |
| 1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | Go to Diagnostic System Check - Vehicle |
| 2 | Verify that the engine fails to reach normal operating temperature. Is the engine failing to reach normal operating temperature? | Go to Step 3 | Go to Diagnostic Aids |
| 3 | Inspect the coolant recovery reservoir for low coolant. Is there a loss of coolant? | Go to Loss of Coolant | Go to Step 4 |
| 4 | Inspect the thermostat for proper operation. Refer to Thermostat Diagnosis . Does the thermostat operate properly? | Go to Step 6 | Go to Step 5 |
| 5 | Replace the thermostat. Refer to Engine Coolant Thermostat Replacement . Did you complete the repair? | Go to Step 6 | |
| 6 | Operate the system in order to verify the repair. Did you correct the condition? | System OK | Go to Step 2 |
Engine Fails To Reach Normal Operating Temperature
Pressure Cap Testing
- Remove the pressure cap.
- Wash the pressure cap sealing surface with water.
- Use the J 24460-01 in order to test the pressure cap. See «Special Tools»(ref-266906-S08992574552007100900000) .
- Test the pressure cap for the following conditions: Pressure release when the J 24460-01 exceeds the pressure rating of the pressure cap. Maintain the rated pressure for at least 10 seconds. Note the rate of pressure loss.
- Replace the pressure cap under the following conditions: The pressure cap does not release pressure which exceeds the rated pressure of the cap. The pressure cap does not hold the rated pressure.
Test Procedure
- Remove the pressure cap.
- Test the operation of the pressure cap. Refer to «Pressure Cap Testing»(ref-266906-S21234705782007100900000) .
- Use the J 24460-01 in order to apply pressure to the cooling system. See «Special Tools»(ref-266906-S08992574552007100900000) . Do not exceed the pressure cap rating.
- The cooling system should hold the rated pressure for at least 2 minutes. Observe the gage for any pressure loss.
- Repair any leaks as required.
Fan Clutch Diagnosis
| Step | Action | Yes | No |
|---|
| DEFINITION: Testing the engagement and disengagement of the fan clutch. |
| 1 | Were you sent here from Symptoms or another diagnostic table? | Go to Step 2 | Go to Symptoms - Engine Cooling |
| 2 | Is there excessive fan air noise? | Go to Step 3 | Go to Step 4 |
| 3 | Fan air noise is normal during cold engine start up. Does the fan noise go away at normal engine operating temperature? | Go to Step 13 | Go to Step 4 |
| 4 | IMPORTANT: The engine must be turned off and the engine temperature should be cold. Rotate the fan clutch.Does the fan clutch rotate? | Go to Step 5 | Go to Step 14 |
| 5 | Visually inspect the fan blades for cracks, looseness or damage. Are the fan blades in good condition? | Go to Step 6 | Go to Step 15 |
| 6 | Visually inspect the fan clutch for signs of silicone leakage. Slight silicone leakage may not effect the fan clutch engagement. Excessive leakage will prevent the fan clutch from engaging. Is the silicone fluid leakage excessive? | Go to Step 14 | Go to Step 7 |
| 7 | Inspect the fan clutch for proper installation. Move the fan blade back and forth in a lateral motion. Inspect for fan blade to fan clutch movement. Is the fan blade loose at the fan clutch? | Go to Step 10 | Go to Step 8 |
| 8 | Inspect the fan clutch for wear. Move the fan blade back and forth in a lateral motion. IMPORTANT: Approximately 6.5 mm (1/4 in) movement at the tip of the fan blade is normal. Inspect for fan clutch lateral movement. Is the fan clutch lateral movement excessive? | Go to Step 14 | Go to Step 9 |
| 9 | The fan clutch should have more turning resistance when the engine is at or above normal operating temperature. Does the fan clutch have more resistance when the engine temperature is raised? | Go to Step 11 | Go to Step 14 |
| 10 | Tighten the fan. Refer to Fastener Tightening Specifications . Is the repair complete? | Go to Step 16 | |
| 11 | Perform a fan clutch engagement test. Ensure the engine coolant level is full. Ensure the cooling fan drive belt tension is correct and not slipping. Position and secure a thermometer between the fan clutch and the radiator. Ensure the cooling fan is disengaged before starting this test. Sufficiently cover the radiator grille to restrict the air flow. IMPORTANT: Do not allow engine temperature to exceed 121°C (250°F). Start the engine. Turn the A/C ON, if equipped. Operate the engine at approximately 2,000 RPM. Note the thermometer reading when the fan clutch engages. Do not continue this test if the fan clutch does not engage between 85-96°C (185-205°F). Fan clutch engagement will be indicated by an increase in fan air noise, fan speed and a temperature drop of about 3-10°C (5-15°F) on the thermometer. Did the fan clutch engage between 85-96°C (185-205°F)? | Go to Step 12 | Go to Step 14 |
| 12 | Once the fan clutch engages, perform the following steps: Uncover the radiator grille. Turn the A/C OFF, if equipped. Operate the engine at approximately 2,500 RPM to reduce the engine operating temperature. Remove the thermometer. Did the engine return to normal operating temperature? | Go to Step 13 | |
| 13 | As the engine temperature returns to normal, the fan clutch will disengage, indicated by a reduction in fan air noise and fan speed. Did the fan clutch disengage? | Go to Step 16 | Go to Step 14 |
| 14 | Replace the fan clutch. Refer to Fan Clutch Replacement . Is the repair complete? | Go to Step 16 | |
| 15 | Replace the fan blades. Refer to Fan Clutch Replacement . Is the repair complete? | Go to Step 16 | |
| 16 | Operate the fan clutch to verify proper operation. Did you find and correct the condition? | System OK | Go to Step 2 |
| IMPORTANT |
|---|
| The engine must be turned off and the engine temperature should be cold. |
| IMPORTANT |
|---|
| Approximately 6.5 mm (1/4 in) movement at the tip of the fan blade is normal. |
| IMPORTANT |
|---|
| Do not allow engine temperature to exceed 121°C (250°F). |
