There has been much talk about just what oil to use in a VW engine !! 
Here is what i have found.  
What NOT to use :  Castrol GTX  10/30  Engine runs very hot, idles rough 
What i use now:   Valvoline High Mileage 10/30 in winter and 10/40 in the 
                          summer. 
The Valvoline High Mileage oil is part synthetic and seems to keep the engine
running cooler and the idle speed increased after the first change over to 
the Valvoline oil.  The engine now runs much smoother, no hick-ups or 
sputters.  The oil is also visibly cleaner over the same period of mileage. 
Now the conditions here in the desert are different than in cooler climates. 
My neighbor ( Morgan ) runs a desert Baja rail and he was the one who 
told me about the Valvoline oil.  He runs the same 1600 engine that i have, 
and has not had a failure in the past 6 years.  He runs a lot harder and faster 
than i do in my stock body 67 Bug !!!  I only run on paved roads ........  
Now that i started this frakess !!!  Lets get your input.  Positive or Negative  
Thanks      Yuma    ( Sonny )