VW G11 Specification Antifreeze / Engine Coolant
Volkswagen models manufactured before 1997 used G11 coolant, typically coloured blue. G11 VW coolant should not be mixed with the later G12 coolant but *can* be mixed with the G12+ and G12++ coolant that supersedes both G11 and G12.
G11 coolant is not a longlife coolant and should be replaced every 12 months. If you are unsure as to what kind of coolant you have, the safest option is to drain, flush and replace with longlife VW G12++ coolant. VW G11 is also known by VW reference TL 774 C and equivalent to the VW blue coolant part numbers G011000 and VW-W043611.