Interesting stuff bruce. I mentioned I recently filled up with synthetic 10w 60 to try it. Don’t know what to say about the non uniform looking oil you mention. I’ve just noted a bit of oil pressure increase over 20w 50 when oil temps at 90C ( highest I’ve been able to get around town ).
I chose the oil to see if it would keep pressure reasonable at 100C . Hope to find out in a week or so , going on a trip .

Alistair 

> On Aug 9, 2022, at 3:02 PM, Bruce Todd <beeceetee@gmail.com> wrote:
> 
> Lots of opinions on oil - that is for sure.  For a brief period I was using
> 10 W 60 synthetic but last summer after getting some work done on my engine
> at a well known VW shop - one of the mechanics showed me a sample of the
> oil which did not look uniform and told me they changed it back to 20W 50
> non synthetic.  This place has a good reputation and services both Audis
> and VWs including Vanagons and has lots of synthetic oil available - so it
> is curious why they went back to using conventional on my Syncro.  In fact
> any place I have taken my van for servicing where the oil has had to be
> changed - it has always been conventional oil that it has been refilled
> with.  Perhaps a cost savings measure - or perhaps what is best for these
> old motors?
> 
> Bruce
> 
>> On Sun, Aug 7, 2022 at 9:15 AM OlRivrRat <OlRivrRat@comcast.net> wrote:
>> 
>>        I always get curious, when I hear of NonSynthetic 20w50 being used
>> in
>> 
>> a Vanagon H2OBoxer Eng, as to what prompts the user to do that ~
>> 
>> 
>> 
>>>> On 7 Aug , 2022, at 9:41 AM, Dan N <dn92610@GMAIL.COM> wrote:
>>> 
>>> thank you Dennis,
>>> 
>>> I wonder if there's something to do with the oil grade they recommend
>> with
>>> the RPM of the engines... On my ML430 suv it's about 2K rpm at 70mph...
>> On
>>> the vanagon it's 4K at 70mph. At 55mph it's about under 2K rpm for the
>> suv
>>> and about 3K rpm for the vanagon. The suv uses 5W40 synthetic, I use
>>> non-synthetic 20W50 on the vanagon.
>>> 
>>> On Sun, Aug 7, 2022 at 7:37 AM Dennis Haynes <d23haynes57@hotmail.com>
>>> wrote:
>>> 
>>>> Recently there was some discussion on engine oil. So I'll add more
>>>> thoughts to the discussion.
>>>> Recently I acquired a 2022 GMC Sierra Crew Cab, Denali. Has the 6.2L and
>>>> 10 speed Allison. Will soon be having its 1st oil change done. Part of
>> GM's
>>>> plan to improve fuel economy is the use of low viscosity lubricants. The
>>>> engine calls for 0w-20, the transmission use special low viscosity ATF,
>> and
>>>> even the axles call for 75w-80. I having a hard time wrapping my head
>>>> around using the 0w-20 oil for an engine of this horsepower. To add to
>> the
>>>> confusion the hopped version of this engine for the Corvette calls for
>>>> different oil.
>>>> 
>>>> So doing some research I learned something that I never gave thought to.
>>>> Engine oils contribution to an engine going into pre-ignition. Makes
>> sense
>>>> given some thought. There is always some oil on the cylinder walls and
>> some
>>>> part becomes part of the combustion process. For the Waterboxer this is
>>>> relevant as there is also some oil laying in the bottom of the cylinder.
>>>> For my engine it has active fuel management, (AFM). Glorified cylinder
>>>> deactivation. Under certain load and speed conditions the cylinders get
>>>> deactivated via a dance of turning off the injectors, and de-activating
>> the
>>>> valves. In this state oil that gets past the rings isn't burning off.
>>>> 
>>>> GM addresses this as part of their Dexos specifications. The oils
>>>> contribution to detonation is also of concern for engines that are
>> direct
>>>> injected and turbo charged.
>>>> So to add to the confusion there is Dexos 1, generation 1, 2, and now 3,
>>>> and Dexos 2. Now one would think that Dexos 2 would be the later or
>>>> improved spec. It is not. Dexos 2 is for europeant vehicles which
>> addresses
>>>> that many European vehicles are Diesels. The performance for spark
>> ignition
>>>> engines is actually lower.  The GM specs also include other ratings that
>>>> also include fuel economy. Oils that carry the Dexos 1, generation 2 or
>> 3
>>>> rating is limited.
>>>> 
>>>> How does this apply to us? There are a number of folks that think heavy
>>>> duty Diesel oils are a better choice for the Waterboxer. The
>> pre-ignition,
>>>> detonation control is just another consideration for using oils that are
>>>> designed for gasoline, not diesel engines. Pre-ignition is the cause of
>>>> most melted pistons and a contributor to rod bearing failures. For the
>>>> Vanagon it is of significant concerns as due to all the other noise and
>>>> design of the engine it is not easily heard when it occurs.
>>>> 
>>>> Dennis
>>>> 
>>