Date:         Tue, 25 Apr 1995 12:22:30 -0600 (CDT)
Sender:       Vanagon Mailing List <vanagon@vanagon.com>
From:         Jerry Dunham <dunham@devnull.mpd.tandem.com>
Subject:      Re: Fuel and Oil for a Vanagon?

]Date: Tue, 25 Apr 95 12:00:35 CDT
]From: Joel Walker <JWALKER@ua1vm.ua.edu>
]
]On Tue, 25 Apr 95 10:24:15 CDT Ron Lussier said:
]>     1) Is synthetic oil good to use in a 1990 Vanagon?  (Mobil 1 or equiv.)
]>        I've always used it in my 1987 golf, and I think it's one reason the
]>        engine is in fantastic shape.
]
]well, my personal feeling is that it ought to be ok. but i've never used it.

[snip]

]so. are synthetics good oils? yeah. i guess. but all my brother and the other
]fellows could figure was that synthetics are very very very small-moleculed
]and WILL find any and all tiny cracks and holes to leak. whereas the dino-oils
]are bigger molecules (or whatever the correct term is) and kinda "clog" them-
]selves against those tiny cracks and holes.

Interesting, but I've never heard of this before.  The REAL test would
have been to go BACK to the synthetic and see if the leak reappeared.
Otherwise, a just-as-valid conclusion could be that it just needed
another week.

]also: i think the tendency to want to run the synthetics is mostly the desire
]to go longer mileage between oil changes. i personally think this is a very
]BAD idea. i've read a bunch of stuff in books and articles and had my own
]oil analyzed by a chem lab several times ... and my conclusion is that you
]should change the oil frequently to get out the combustion by-products that
]the filter does NOT get out: stuff like acids and small metal particles and
]carbon particles. the "crud" that is still in your oil is amazing. and the
]filter only gets the big stuff.

I agree with this 100%.  Synthetic oils DO last MUCH longer without
breaking down, but there are lots of other factors: combustion by-
products, fines (small wear particles), additive package breakdown,
other contaminants.  If you really want to USE the extended life of a
synthetic, you need to add a bypass-type centrifugal oil filter to take
out the fines (used by some long-haul trucks), plus make certain that the
additive package in the synthetic you choose can stand up to the longer
mileage.  Then you STILL have the problem with combustion byproducts that
are acidic.  Just going to a synthetic without any other changes and
thinking you can go to extremely long oil-change intervals is a mistake.

]so the idea of leaving all that in the engine for 7500 miles really bothers
]me. i've gone to changing oil at 2500 miles (instead of the old 3000) and
]wonder if i ought not to change it every 1500. but 2500 seems to me to be
]a good compromise of money, time, and engine care.

I've used 3000 miles as my interval for decades, and believe I've had
excellent results.  I use a quality dino juice (Castrol GTX) and always
change the filter.

]>     2) How about fuel?  I've always fed my Golf the highest octane available,
]>        but I've been told that this is essentially a waste.  Opinions?
]
]so far, i cannot detect any difference in mileage or performance between the
]six brands and three octanes that i use.

[snip]

]but the bus doesn't seem to care, one way or the other. so far i've run about
]400 gallons of each of the six brands in 87 octane, and about 150 gallons of
]each in 89 and 92 octanes.

Bingo.  Higher octane ratings are there to minimize the tendency to pre-
ignition, nothing more.  You should always run the lowest octance that
does not result in pinging in your engine.  This can sometimes change as
an engine ages (it has in my wife's Honda, now at 123,000 miles).  Any-
thing more is a waste of money and petroleum resources.

The only exception occurs in vehicles that use a knock sensor to control
timing (and, sometimes, turbo boost).  In these cases the engine will adapt
to whatever octane you give it, giving better power and driveability with
increasing octane.

-- 
-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
Jerry Dunham, MSE          hoosier@rider.cactus.org           (512)432-8598
Tandem Computers, Inc.        Atarian ordinaire       dunham@isd.tandem.com
Integrity Systems Division         GS650G           dunham_jerry@tandem.com

          Politicians are like ships: noisiest when lost in a fog.