When the engine is running, the red indicator light flashes
Too little coolant in circulation system
The expansion tank must be filled to the maximum mark. Add fluid if necessary Check the cooling system for leaks.
The thermostat does not open. Coolant circulates only in the small circuit
Check if the outlet is heating up (upper) radiator hose. If not, remove and check the thermostat. Replace if necessary.
Faulty water pump
Remove and check the pump.
Faulty coolant temperature gauge
Check the sensor and pointer on the instrument panel.
Expansion tank cap defect
Check the pressure cooling system.
Radiator fins dirty
Blow out the radiator from the engine side with compressed air.
Radiator clogged with lime deposits or rust. The radiator warms up only at the top, the lower radiator hose remains cold
Replace radiator.