>I went to the local FLAPS and bought a rubber plug, (1/2 inch if I 
>remember).
>I had to hacksaw the collar/head of the plug, since it didn't fit into 
>the (slightly) recessed hole of the '87 Vanagon.
>12K miles and no leaks (with Mobil One synthetic, no less).

I had the cheapest possible plug in a '78 I bought without checking over 
(never trust a VW dealer BTW)  A hollowed out flanged rubber cork you jammed 
into the drain hole using 1/4" stick/ballpoint pen etc.  You tore it out 
with pliers.  Reusable of course. Wept oil very slightly, but worked for 6 
years.  Must find a couple to throw in the glove box.   Tim Smith