If you go to synthetic, it is advisable to change the filter more
frequently than the oil, on a 4-1 or 3-1 basis.  You'll need to add a
bit of fresh oil to make up for what comes out witht the filter.  The
synthetic doesn't break down like normal oil, but it does get crud in it
and clean filters are necessary.  Another good idea would be to use a
filter that takes out smaller particulates than normal FLAPS filters.
Amsoil/amsoil dealers has/have info about use of synth oil in engines,
change intervals and filters.

I thot about doing this with redline oil, but eventhough i wasn't
replacing all the oil as frequently, it still was not cheaper than just
using non-synth oil and changing oil and filter every 3-4000 mi.

using synthetic in the transaxle is much more worthwhile.
later,
fred

Sorin Bejenaru wrote:
>
> Looking through the VW Vanagon Maintenance booklet I was surprised to see
> that VW recommends changing oil at every 7500 miles and changing the oil
> filter at every 15000 miles.  All mechanics that service cars say that oil
> should be changed every 3500 miles together with the oil filter.  Is this
> simply providing more work for the mechanics or can the oil really work OK
> up to 7500 miles?
> Also if using syntetic oil, should that make it OK to increase the mileage
> between oil changes?
>
> Thanks for your input.
>
> Sorin Bejenaru