Engine Coolant

RS2K said:

I agree on the non mixing btw. Brand specific though? Nah. It's not as if VW engines are made of different metals.

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http://en.wikipedia.org/wiki/List_of_Volkswagen_engines
http://stason.org/TULARC/vehicles/v...my-cooling-system-Where-can-I-get-phosph.html

Hard to know. They use grey cast iron in older engines and hypereutectic aluminum-silicon alloy ALUSIL in newer ones. Seems like they describe the new engines in similar terms like aluminum, light aluminum, hypereutectic aluminum, etc. These are probably all the same or so similar as to make no difference to the coolant. That said VW seem specify different coolant for different engines, some are not interchangeable. Which suggests otherwise.

http://www.geocities.com/MotorCity/1108/coolant2.html

VW issued a Technical Service Bulletin (TSB 199601) which states that the
blue G11 coolant causes corrosion to the aluminum head. The TSB says to
change to the new red G12 coolant. If you would like to see this TSB, just
go to your dealership and ask to see it. Yes, you are authorized to see it
no matter what they tell you! Also if your coolant is brown, its seen
better days and needs to get changed.

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http://forums.vwvortex.com/zerothread?id=1696736

Do not screw around with different coolant types and VW's. Use only G12 coolant that you purchase at the dealer. VW makes/sells excellent coolant. Use distilled water to mix with it and follow the mixing directions exactly.Definitely do not mix Green ethylene glycol anit-freeze with the pink stuff- the result is mud.
The aluminum deteriorates and electrolysis occurs with plain old anti-freeze.

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...VW put out a service bulletin warning against mixing its own coolant (G-12) with its older, G-11 coolant. We'll have to take its word for it, as we're not willing to sacrifice any of our customers' VW engines to test the theory....

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