Warning! Wait until the engine has cooled down completely before proceeding with the procedure. Avoid contact of antifreeze with eyes, exposed skin, and painted surfaces of the car body panels. Wash off accidental splashes immediately with plenty of water.
1. To check the coolant definition, a special tester is required - ask in car accessory stores.
2. After the engine has cooled down completely, unscrew and remove the filler cap of the expansion tank. Following the instructions of the tester manufacturers, make sure that the mixture of antifreeze and water poured into the system provides the required frost resistance. If the density of the mixture is insufficient, the system should be drained and the coolant replaced (see section Replacing the coolant).
3. After completing the measurement, check the coolant level in the expansion tank (see section Weekly checks), then tighten the filler cap securely.
(Information copied from the resource www.SkodaBook.ru)