Scott, you are right on. I ran the same wt. oils...except Texaco Havoline in my
1.9 "85 GL all those years I was in Alaska and had 205,000 miles on her without a
lick of trouble. I did use a block heater in winter.

John Rodgers

Scott De Santi wrote:

> I<< BTW, isn't Castrol Synthetic 5W-50 more suitable for VW's than Mobil 1
>  15W-50 simply by offering lower viscosity (5W) for winter time? >>
>
> Hello Volks,
>
>     We've been watching this oil thread roll on for some time now... and
> nobody has even asked about the viscocity ranges of oil and how they are
> produced.  A mechanical engineer friend once told me that special additives
> are used that respond to heat and form 'chains'  which thicken the oil as it
> get warmer.   He also told me it was wiser to keep the range of the
> multi-weight oil to no more than 30 i.e. 10W-40 or 20W-50.  His reasoning was
> that in order to make such large ranges like 5W-50, the ratio of additives to
> actual oil is too high for optimal lubrication.  I haven't done any other
> research on this, perhaps the engineer types on the List could provide some
> information.   FWIW, in Anchorage, I run 20W-50 Mobil 1 in the "Summer" and
> 10W-30 Mobil 1 in the other 9 months.
>
> Yours in the Quest for Knowledge,
> Scott De Santi
> 86 Vanagon 2WD (Wobbly Bus)
> Anchorage, Alaska