Coolant overheat warning light comes on.
Check coolant in expansion tank. Is coolant level too low? → Add coolant.
↓ No
Check thermostat. Thermostat does not open. Is the left radiator warmer than the right one, and the coolant pipe to the water pump hot? → Replace thermostat.
↓ No
Test the water pump. Is water pump faulty? → Repair/replace water pump.
Fan motor does not cut in.
↓
Check fuses. Fuse blown? → Replace fuse.
↓ No
Check fan relay. Fan relay defective? → Replace fan relay.
↓ No
Check electrical circuit. Poor contact/open circuit? → Make good contact/eliminate open circuit.
↓ No
Check fan motor. Fan motor defective? → Repair/replace fan motor.
↓ No
Check thermostat. Thermostat does not open. Is the left radiator warmer than the right one, and the coolant pipe to the water pump hot? → Replace thermostat.
Excessive loss of coolant.
Check coolant circuit. Coolant circuit is interrupted or leaking? → Reconnect or repair leak, as applicable.
Engine remains cold or warms up very slowly.
↓
Check thermostat. Thermostat does not close. Are both radiators equally warm and the cool- ant hose to the water pump cold? → Replace thermostat.