Volkswagen Golf GTI 2016, Owner'S Manual, Page: 1088 / 1341

Please first read and note the introductory information and
heed the WARNINGS →
Introduction
The engine cooling system is filled at the factory with a mixture of
specially conditioned water and at least 40 percent of Volkswagen
engine coolant additive G 13 (TL-VW 774 J). This engine coolant
additive is pink.
This mixture provides antifreeze protection down to -13 °F (-25 °C).
It also helps to protect the light alloy parts in the engine cooling
system against corrosion. In addition, the mixture helps prevent
calcium deposits and increases the boiling point of the engine
coolant.
To protect the engine, the mixture must always contain at least 40%
coolant additive even in warm weather or climates where antifreeze
protection is not needed.
If more antifreeze protection is needed for climate conditions, the
percentage of coolant additive can be increased. However, the
coolant additive percentage must never be more than 60%;
otherwise, antifreeze protection is reduced and the ability of the
mixture to cool the engine is also reduced.
When adding engine coolant, use a mixture of distilled water and at