Diagnostic Aids
The engine may fail to reach normal operating temperature due to an intermittent operation of one of the following components:
| • | The thermostat |
| • | The electric fan system |
| • | The mechanical fan system |
For electrical inspection of the electrical fan system, refer to Testing for Intermittent Conditions and Poor Connections .
Step | Action | Yes | No |
|---|---|---|---|
DEFINITION: Normal coolant temperature readings will be expected to vary from 88-104°C (190-220°F). | |||
1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | |
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 surge tank 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 |
