Antifreeze is a means of protection against freezing (Audi A3 8L)

The engine cooling system is filled with a mixture of water, antifreeze and AUDI corrosion-protective components throughout the year. This mixture prevents freezing and corrosion of system components, as well as the formation of limescale deposits, and increases the boiling point of the liquid. Due to the expansion of the coolant when heated, excess pressure occurs in the system, which also contributes to an increase in the boiling point of the liquid. The liquid pressure is limited by a safety valve located in the expansion tank cap, which opens at a pressure of 1.2 - 1.5 bar. Increasing the boiling point of the liquid is necessary for the reliable operation of the engine cooling system. At a low boiling point of the liquid, thermal stagnation may occur, as a result of which the efficiency of liquid circulation and engine cooling is reduced.

For vehicles with chassis number up to "8LVA006233" (released at the end of 1996.) aUDI G11–A8C antifreeze is used in series. G11–A8C or another one marked "according to TL–VW 774 C" can be used to supplement the system. The green color is a sign of this antifreeze.

Starting from chassis number "8LVA006234", antifreeze G12 is used serially. G12 or another antifreeze marked "according to TL–VW 774 D" can be used to supplement the system. The indicator is the red color.

Warning: Do not mix G11 and G12, this may cause severe engine damage. The mixture is brown in color. It must be removed immediately.

Warning: Engines with a cooling system filled with G11 antifreeze can be converted to G12 antifreeze. To do this, completely drain the liquid from the cooling system. Then fill the system with clean water and let the engine run for 2 minutes. After that, drain the water from the system and blow it with compressed air through the expansion tank, which ensures complete removal of water. Close the plug and fill the system with a new mixture of water and G12 antifreeze.

Warning: Use only water/"G12" AUDI mixture (red color), even in the warm season. The water must be clean and must not contain lime. In the summer, the antifreeze content in the coolant must also not be lower than 40%. Therefore, when adding water to the system, it is necessary to also add antifreeze.

Coolant composition, l

Protection	up to –25°C
G12	2.0 l
Water	3.0 l
Protection	up to –35°C
G12	2.5 l
Water	2.5 l
Filling volume	5.0 l

In our latitudes, protection against freezing should be provided up to a temperature of -25°C, better up to -35°C. The proportion of antifreeze cannot exceed 60% (protection up to -40°C). Otherwise, the degree of protection decreases and engine cooling deteriorates.