I use Castrol Syntec 5w50 with a Mobil 1 filter, very happy with it.
Seems to give me a quicker warm up than my old 20w50 did. A little
pricey but I think the engine benefits from the lower viscosity at start
up. Instead of being gooped in the pan at startup, it is a easy flowing
liquid that will get pumped through the engine quickly.
Just my opinion which is worth about what you paid for it ;-)
Steve Hajasz
90 Vanagon GL
90 Vanagon ( Head are coming out for new gaskets, Auto tranny is next!)
84 Rabbit Convertible

>        I was thinking of switching to Synthetic Oil in my '87 Westy.  I
>went looking for some and find there is no 20w50.  So........those of you
>that are using Synthetic in your wasserboxer engines what grade are you
>using ?  5w50 ?  15w50 ? These are two grades I saw available that I think
>would be right. Is this a good plan ?
>
>Cheers
>
>Frank