it all depends..
mainly on the temperature environment you operate your van in,
and age of the engine.

I have used lots and lots of Chevron Delo 15W40 over the years.
you'll notice now it's LE - low emissions formula ..means less zinc ..
and therefore is more for newer roller cam follower engines, and not so much
for flat cam follower engines like our waterboxers.
    I regard Delo 15W40 as 'just ordinary' ....these days, like 'ok ..but
nothing special.'

I go more for Shell Rotella or similar 15W40's aimed at diesel engines ..
they may have zinc still.
( you can also just buy zinc addtive and put it in the oil - at most any
FLAPS ) ..

for a synthetic, I like Mobil 1,  15W50.
oh ..
and for sure, Royal Purple 15W40 .
righ now that is my favorite non-synthetic 15W40 .....I recommend it highly.

for a mild climate ...
and not super new engines that want 5W30 or whatever...
I just use 15W40 year round usually.

Scott
www.turbovans.com
----- Original Message -----
From: "Michael Sullivan" <sandwichhead@GMAIL.COM>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Friday, March 04, 2011 11:13 AM
Subject: Top 3 Oils for 2.1 Again

>I have used DELO 15/40 and I know Mobil One is good, but what are the top 3
> and the best weights?  20/50?  Thanks.
> Michael in San Antonio
> 91GL Weekender AT 2.1L 'Gringo'