Aluminum Oil Pans on later VWs?

[rocco16 at sbcglobal.net (Larry Fry)]

> At some point just  recently though, VW made a new oil pan that is half 
> aluminum/half  steel.  The steel portion covers the bottom and up along 
> the sides to  about halfway up the pan.

I'd like to see how this part is fabricated, since the only way I know to 
join these two metals is by adhesive bonding, and I don't think the cost of 
that method would be very attractive to VW.
 What would be the possible advantage for a "composite" fabrication like 
this...?   A full aluminum casting would have many more advantages besides 
being cheaper.

Larry
sandiego16v