>This is caused by the thick rubber gasket allowing coolant to seep
>under it when under pressure.  This forms little pools of trapped coolant
>and it is the concentration of ions and depleted oxygen that's causing
>electrical gradients to form. This is referred to as CREVICE corrosion, and
>any book on corrosion will cover it in detail. The book will also tell you
>NEVER use compliant gaskets in a system subject to corrosion. Plain and
>simple, VWs designer screwed up on this. They were mechanical engineers, not
>corrosion types.

Thanks. That was fascinating.

Can you stop/minimize this by simply changing the gaskets out, say every
two years? How do some people get them to go 200K without maintaining them
where the others leak at 50K?

--Ken
  Boxers, no water ever