Engine temperature too high
- Faulty temperature unit (indicator) or thermosensor
- Thermostat stuck closed
- Faulty radiator cap
- Insufficient coolant
- Passages blocked in radiator, hoses or water jacket
- Air in system
- Faulty cooling fan motor
- Faulty fan motor switch
- Faulty water pump
Engine temperature too low
- Faulty temperature unit (indicator) or thermosensor
- Thermostat stuck open
- Faulty fan motor switch
Coolant leaks
- Faulty water pump mechanical seal
- Deteriorated O-rings
- Faulty radiator cap
- Damaged or deteriorated cylinder gasket
- Loose hose connection or clamp
- Damaged or deteriorated hoses