Date: Sun, 11 May 2014 11:40:55 -0700
Reply-To: Stuart MacMillan <stuartmacm@GMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Stuart MacMillan <stuartmacm@GMAIL.COM>
Subject: Re: Royal Purple Motor Oil..
In-Reply-To: <CC597B0D-AC31-49DC-AC40-B24CAAD4738A@comcast.net>
Content-Type: text/plain; charset="us-ascii"
The thing about multi weight oils is that 15w- or 20w- oil is physically
thicker (higher viscosity) than a 5w- anything, and that makes a big
difference in our loose WBX'ers. The rating is a lubrication protection
rating, and 5w- oils are thinner to provide for better gas mileage in modern
cars. At high temps an Xw-50 protects like a straight 50w because of
additives and composition, but is physically much thinner.
On my '85 purchased in 2012 with 135k on it, I started with 15w-40 dino oil,
and my hot oil pressure was 28 @ 4000rpm, and 8 at idle, very near the lower
limit. I now run Mobil 1 15w-50 with a Mobil 1 high efficiency filter
(Dennis Haynes recommendation) and my OP is 32 @ 4000, and 10 at idle.
Better. Next time I might try someone's synthetic 20w-50, which will be
thicker yet.
Interestingly, upon cold start @ 60 degrees F with either oil, the OP is 60
at idle and does not go higher. Within 5 minutes of driving it drops to 20
at idle, and 40 at 4000. 30 minutes at 60 mph and it's at the low levels.
That's the case expanding with heat and opening the main bearing tolerances,
a design feature every flat VW engine has!
I also think everyone should have an oil pressure guage. Coupled with oil
analysis, you'll know what's really going on with your engine. My first
analysis on this rig was not very good, and I'm sending another sample soon.
I live in Seattle where the temps are moderate, but travel in hot eastern
Washington too, so I run this oil year around.
Stuart
-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
OlRivrRat
Subject: Re: Royal Purple Motor Oil..
John
There are a LotOfFolks that say it is OneOfTheBest if not TheBest
but IMHO it is not better enough to justify the Extra$s ~ I'm curious as to
why you are wanting to shift from 15W-50 to 20W-50 as they are both 50weight
oils when WarmedUp & Unless you live in a Climate that is like they get in
the Southern1/2 of Arizona or NM or Texas & you are being told by an
OilPressureGauge that your Eng' is Old&Loose there is no need for the Number
BeforeThe "W" to be any higher than 5 ~