Slippery business this.  Some time ago, for the greater good, Oil MFGR's had
to stop putting zinc compounds into their automobile oil.  lGeegling around
for zinc in motor oil will get you a wealth of opinon and fact.

Ed Hackett formerly of Desert Research Institute put together an informative
bit here:
http://micapeak.com/info/oiled.html.

Pensionerd.  (Rotella-fella)

On Mon, Jan 11, 2010 at 3:14 PM, Dave Mcneely <mcneely4@cox.net> wrote:

> I use Castrol 20W50, petroleum based (nonsynthetic).  I change the oil
> every 3000 miles, just as I always have for all my vehicles.  I can't
> imagine how synthetic could improve on that.  I notice that most
> manufacturers specify that oil should be changed at the recommended
> interval, and that less often than that voids the warranty, whether the oil
> used is synthetic or not.  David McNeely
>
>
>
> On Mon, Jan 11, 2010 at 1:46 PM, Stephen Cebula wrote:
>
> What motor oils you you all use out there?  A friend of mine keeps pushing
>> synthetic oil.  He's a Ford man, and not familiar with Vanagons.  What's the
>> rap on that?
>> Steve
>>
>