| Symptoms |
POSSIBLE CAUSES |
REMEDY |
| Coolant Leakage |
- From the thermostat gasket
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Check the mounting bolts |
- Check the tightening torque of the mounting bolts.
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- Retighten the bolts and check for leaks again.
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| Make sure the seal is not damaged. |
- Check the gasket or seal for damage.
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- Replace the gaskets and reuse the thermostat.
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| Excessive cooling |
- Reduced heating performance (cold air is supplied)
- Temperature gauge indicates "LOW"
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Visually inspect after removing the radiator cap. |
- Insufficient coolant or leakage.
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- After refilling the coolant, check again.
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| Check using GDS and start the engine |
- Check the diagnostic trouble codes
- Check the fan clutch connection or the fan motor.
If the fan clutch is still engaged, noise is heard during slow motion. |
- Check the connectors, wiring and engine coolant temperature sensor.
- Replace the components.
|
| Remove the thermostat and check. |
- Check the thermostat valve for dust or debris.
- Check the thermostat valve for sticking.
|
- Clean the thermostat valve and reinstall the thermostat.
- Replace the thermostat if it does not operate properly.
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| Overheating |
- Engine Overheat
- Temperature gauge indicates "HIGH"
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Visually inspect after removing the radiator cap. |
- Insufficient coolant or leak. Be careful when removing the radiator cap if the vehicle is overheating.
- Check for air in the cooling system.
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- After refilling the coolant, check again.
- Check the cylinder head gasket for damage and the tightening torque of the mounting bolts.
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| Check using GDS and start the engine |
- Check the diagnostic trouble codes
- Check the operation of the fan motor when the temperature changes.
- Check whether the fan clutch is slipping.
- Check the water pump for seizing or rotor damage.
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- Check the connectors, wiring and engine coolant temperature sensor.
- Check the fan motor, relay and connector.
- Replace the fan clutch if it does not operate properly.
- Replace the water pump if it does not operate properly.
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| Immerse the thermostat in boiling water and check. |
- Check whether the thermostat opens at the valve opening temperature.
Check whether the thermostat opens at the valve opening temperature. |
- Replace the thermostat if it does not operate properly.
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