Volkswagen Golf GTI 2016 Owner's Manual page 1089

least 40% coolant additive - G 13 - or - G 12 plus-plus - (TL-VW 774
G) for optimum corrosion protection →
Do not mix - G 13 - with - G 12 plus - or - G 11 - . Mixing these
coolant additives together significantly reduces corrosion protection
→ and can lead to engine damage that is not covered by any
Volkswagen Limited Warranty.
WARNING
Too little antifreeze protection in the engine cooling system can
cause engine failure and severe injuries.
Always make sure there is enough of the correct coolant
additive to provide proper antifreeze protection at the coldest
temperatures that can be expected where the vehicle will be
used.
At extremely cold temperatures, the coolant could freeze,
causing the vehicle to break down. The heater would also not
work, and vehicle occupants could be without protection at
subfreezing temperatures.
.