>Perhaps some dissolved zinc in our coolant would work, being preferred
>in the red/ox reaction to the aluminum of our heads?  Any chemists or
>metallurgists out there who could comment on this?  I am not certain of
>all the details but I believe the concept is correct...although if it is
>wouldn't VW have simply added this "anode" material to the Autobahn
>coolant to prevent/eliminate the leakage issue and all the irate
>wasserleaker owners...have changes been made to the coolant since the
>leakage problem arose?  I suppose that would make regular coolant
>changes absolutely mandatory to insure that the "anode" material has not
>been completed consumed by the reaction.

        It's interesting that this thread would surface at this time...
        While watching a NASCAR event last Sunday, I didn't pay much
        attention to the commercial for a new product called "Rad Cap"
        which purports to provide *exactly* this sort of protection.
        Unfortunately its form factor (normal radiator cap) is wrong for
        the Vanagon cooling system :-(

        Later I saw it again in the MotorTrend October 98 issue "Car Care"
        section...see http://www.motortrend.com/oct98/cc/cc_f.html

        A "RAD" SOLUTION TO ALUMINUM EROSION

        The Rad Cap offers an innovative approach to minimizing the type of
        internal metallic erosion caused by electrolysis: the stripping of
        ions from system metals due to stored electricity in the cooling
        system. Based on a concept used in marine applications, the Rad Cap
        contains a sacrificial magnesium anode that hangs from the underside
        of the cap and is immersed in the coolant. The idea is that magnesium
        is a more active metal than aluminum, so it will dissolve before
        aluminum, saving wear on the engine's aluminum parts. According to the
        company, proof that it works is evident from the fact that the
        electrical voltage in the solution is usually much higher around the
        anode than elsewhere in the coolant. The Rad Cap costs about $20, and
        its effective lifespan is estimated at 18-36 months.
        Contact DD&E, 925/689-6214.

      OLTECO                    Ari Ollikainen
      P.O. BOX 3688             Networking Technology and Architecture
      Stanford, CA              Ari@OLTECO.com
      94309-3688                415.517.3519