Coolant and Heating recommended brands
G12 Plus Plus is the latest VW variant of this product Still Violet in colour and 5 year change cycle (original non organoacid types only lasted 2 years). There is also G13 (meets newer EU regulations) although 80/90 still discussing whether is OK to use.
G12 is the original VW standard for red. G12+, G12++ and G13 are updates on it, backward-compatible.
VW G12+ its pink and can mix with previous versions of VW coolant
GSF  do it for £4.50 for 1.5Litres (concentrate, makes double)
Avoid non-recommended brands as the T25 WBX is prone to corrosion on parts that the coolant comes in contact with (i.e the bolts that hold your engine together.) If these corrode then when it eventually comes to change your cylinder head these are likely to snap and your engine will bassically need to be rebuilt.
It will take 8 or 9 litres of anti-freeze to fill your system (before diluting) = 6 bottles = £27.00 at GSF
Coolant volume = 16~18 litres
50/50 mix (UK ideal for -30 frost protection, corrosion protection, high boiling point and heat transfer)
HM: I found this G12 information on the web, pretty sure it's official VW, relating to G12 (pink or violet)
◆ Only use coolant additive G 12 in accordance with TL VW 774 F.
Distinguishing feature: coloured violet
◆ G 12 violet (in accordance with TL VW 774 F) can be mixed with the previous coolant additive G 12 red
◆ G 12 and coolant additives marked "In accordance with TL VW 774 F" prevent frost and corrosion damage, scaling and also raise boiling point of coolant. For this reason the system must be filled all year round with frost and corrosion protection additives.
◆ Because of its high boiling point, the coolant improves engine reliability under heavy loads, particularly in countries with tropical climates.
◆ Protection against frost must be assured to about -25 °C (in arctic climatic countries to about -35 °C).
◆ The coolant concentration must not be reduced by adding water even in warmer seasons and in warmer countries. The anti-freeze ratio must be at least 40%.
◆ If for climatic reasons a greater frost protection is required, the amount of G 12 can be increased, but only up to 60 % (frost protection to about -40 °C), as otherwise frost protection is reduced again and cooling effectiveness is also reduced.
◆ The refractometer T10007 is recommended for determining the current anti-freeze density.
◆ If radiator, heat exchanger, cylinder head or cylinder head gasket is replaced, do not reuse old coolant.
Recommended mixture ratios: Frost protection to Anti-freeze amount G 12 / Water
-25 °C > 40% AF/60% Water
-35 °C > 50% AF/50% Water (easiest to mix and best concentration for UK usage)
-40 °C > 60% AF/40% Water (maximum recommended AF concentration )
Use demineralised water
The VAG specification for G12+ antifreeze is TL 774-F (lilac)
The VAG specification for G12 antifreeze is TL 774-D (red/pink?)
The older VW G11 coolant has VAG specification TL 774-C (blue-green,)
Mocki uses Comma Super Coldmaster - Concentrated Antifreeze. Comma have confirmed that this does not meet G12 spec but the xtream red does (however it is more expensive than G12+!)
A while back, I posted that G12 coolant was made by Pentosin.
Just a correction for the record - it appears that G12 is actually made by Valvoline (Zerex), although Pentosin makes a similar, and I believe compatible, coolant.
G12 is Valvoline/Zerex Glysantin G 30, the datasheet for which may be found at 
It was developed in conjunction with BASF, and more info on G12 is to be found at 
The VAG specification for G12 antifreeze is TL 774-D.
In January, 2003, VW/Audi introduced G12+ (part number G 012 A8F A4), an antifreeze with purple coloration. It can be freely mixed with the original pink G12 (part number ZVW 237 G12). The VAG specification for G12+ is TL 774-F. From the information at the above BASF site, Glysantin G 30 meets both specifications. I believe that the only significant difference between the two is the color - changed to help prevent people from thinking that GM Dexcool compatible (typically orange) coolant could be used to top-up the original G12 (pink), which is not the case.
The older, blue-green, VW G11 coolant has VAG specification TL 774-C, and is Glysantin G 48.
Flibbertigibbet: VW Green antifreeze part number ZVW 237 105 is no longer supplied.
It is replaced by the BLUE, RED or PINK, or PURPLE antifreeze. Note: You should not mix BLUE, RED or PINK, or PURPLE coolant with GREEN antifreeze. If you have, you must flush your VW cooling system.
The new PURPLE is fine with PINK...
Peet: System is 17.5ltr. Best corrosion protection and antifreezie properties are offered with G12 from Vw.
Unfortunately works out at aprrox 8 litres, (I'm sure that little bit less won't hurt!!) which even at trade prices worked out at £26 for me recently!!
Tip: If it's a recent rebuild test the sytem with plain water first in case it leaks (!)
When I have topped up always been the pink g12 stuff. Been to garage....4lt was dropped and replaced with a blue coolant? Garage not worried about it...should I be?
Graham81: Yes, g12++ doesnt mix with the blue stuff it turns to sludge, seen it happen on the mk4 golfs.
kevtherev: yep it will sludge up the radiator and heater matrix
.... what are they doing dropping your coolant and putting just 4litres back? was this a repair and so all the coolant wasn't lost? System capacity is 16 litres so needs 8litres for a 50:50 mix.
Ethylene Glycol (old fashioned traditionally blue or green but has older less stable inhibitor pack) 2 year fill.
Organo-Acid Technology (OAT) (later types based on this more modern formulation) 4 or 5 year fill.(pink/orange/puple)
Ethylene Glycol-based 'Hybrid Organo-Acid Technology' (HOAT). Uses Ethylene Glycol but with OAT-based corrosion inhibitors...now these are reported to also be long fill 4/5 years as there inhibitor pack is also OAT based and this is where the grey area arises.
You can't JUST go on colour although it is USUALLY a good indicator of type...However IT ISN'T FOOL PROOF.
I would ask them to show you what they used and if it doesn't mention OAT (organo acid technology and mentions a 2 year change) it is the old stuff and as others have mentioned SHOULD NOT be mixed with newer OAT A/Freeze.
The front heater core is bled by flow rate achieved above 2000rpm.