Chad,
You were the only one who could answer it, so far anyway.
Now, the question is; what is the remedy?  What to do to stop it to happen?  
Does it also mean that the rubber has some electrical conductivity?
Zoltan
  ----- Original Message ----- 
  From: Chad Lyles 
  To: Zoltan Kuthy 
  Cc: vanagon@gerry.vanagon.com 
  Sent: Wednesday, November 28, 2007 1:37 PM
  Subject: Re: What is the scientific explanation?

    this is a from of corrosion caused by a current flow generated between two materials with greatly differing electrical potentials. Contrary to popular belief, galvanism does not occur just between two different metals; it can occur between other materials, such as carbon rubber and a metal. Carbon rubber mated against aluminum, for example, is a disastrous combination that will destroy aluminum very quickly. This is often found in carbon rubber hose joined to aluminum or copper pipes and is often referred to as electro-chemical degradation (ECD) 
   
  hope this helps answer the question. 
  Chad~

  On Nov 28, 2007 12:26 PM, Zoltan Kuthy <zolo@foxinternet.net > wrote:

    I have always wondered, why would there be extensive aluminum corrosion built up under rubber hoses on aluminum parts or under the head gasket.  I don't see any electrolysis activity going on under such insulating material.  I am baffled. 
    Anyone has an acceptable scientific explanation?  Or is it something everyone knows except I.
    Zoltan

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