Dennis Haynes wrote:
> 
> Antifreeze has inhibitors in it already.  Never hurts to add more.  The new
> Long life Anti-Freezes should really help.  New is now required in almost all
> new cars including VW.  In addition, the Vanagon benefits from a "Water
> Wetter" additive.  Available through most diesel suppliers and from Redline.
> This product breaks the surface tension of water eliminating the air bubbles
> the erode heads and cylinders and also improves heat transfer.
>
This URL has all you might want to know about coolants and corrosion in
cars.
A bit technical but useful in understanding complex chemistry.

  
http://triumph.cs.utah.edu/sol/tech/coolant.html

Larry