Examination
Despite the presence of an emergency temperature and coolant level warning lamp, you should not rely on it completely and, from time to time, check the coolant level in the expansion tank in the engine compartment.
The correct check of the coolant level can only be carried out with the engine stopped. The liquid level is visible through the transparent tank even when the lid is closed. When the engine is cold, it should be slightly above the mark «LOW» expansion tank. When the engine is warm, the level should be even higher, but should not cross the mark «FULL».
Topping up
A noticeable loss of coolant indicates a defect or damage. No coolant is consumed or evaporated from the closed cooling system. Only when the engine overheats can some coolant escape through the radiator cap.
There is a risk of injury from hot steam when opening the radiator cap while the engine is warm, so proceed with caution.
Turn the cover through a rag or glove first one turn and bleed excess pressure in the cooling system. Only then fully unscrew the cover.
If water is topped up, the coolant will gradually dilute, so you need to top up the coolant.
Do not add fluid above the mark, as the fluid expands when heated and the excess flows out of the system.
Small amounts of fluid can be added to the reservoir both when the engine is warm and when the engine is cold.
With a significant loss of fluid and a warm engine, cold fluid should not be added to the expansion tank, as this can lead to warping of the cylinder head or cracking in the cylinder block.