Re: synth oil in high milers? A general process.

[Toby Erkson <Toby_Erkson@ccm.jf.intel.com>]

Air-cooled and water-cooled engines are quite different from each other, 
obviously, but are also quite the same, obviously.  So it depends on what one is
doing as to if it will work with both types of engines or only on one.  Applying
the basic principles of engines and oils, below is what I would do for a 
water-cooled, more modern engine.  This is my opinion only and I welcome any 
additional comments (if you send comments to the group then please DO NOT 
include my personal eddress as well).

First, the engine should be in good operating condition so if there are any 
changes in performance, be it good or bad, it can be attributed to the oil 
switchover.

Drain all of the oil and replace the oil filter.  Use a synthetic *blend* oil 
that has about the same weight or whose weight range includes what was 
previously used.  Drive around like you (or she) normally would and try to pay 
attention to the exhaust, looking primarily for excess smoke.  You probably 
should drive behind her before and after the oil change so you can see if there 
is any difference in exhaust smoke.  Also monitor the oil level and see if it is
staying (or dropping) at its normal level (if it consumed oil make sure that its
consumption is at least consistent :)  If everything is okay then after 100-200 
miles drain the oil, replace the oil filter and oil up with the same stuff 
(synthetic blend).  If you can, inspect the inside of the filter (the actual 
fiber/paper element) to see if there's a lot of crap in it or not (a hacksaw 
works great!).  Hopefully, there won't be.

Continue to monitor the oil level and exhaust, just to make sure, and keep this 
in her car up to 1000 miles (see item 2 below).  If everything is still okay 
then change the oil filter and replace the oil with the same stuff.  Continue up
to the normal oil change interval or 3000 miles, whichever comes first, then:

 1.  If everything is still hunky-dory then change the oil, oil filter, and use
 your/her favorite pure synthetic (mine is Mobil 1).  Monitor oil level and
 exhaust closely.  Pure synthetic and blends are stiff different animals!
   a.  If everything is still fine then at the halfway point of the normal oil
   change interval change the oil and oil filter.  Fill up with the same oil and
   continue with the normal oil change interval.  After a couple of normal oil
   changes it may be safe to lengthen the oil change intervals, up to double the
   time span, at your discretion.
   b.  If there are problems then switch back to the blend (after changing the
   oil and oil filter).  This will offer her a little more protection than plain
   conventional oil.  Oil change intervals should remain the same, however.

 2.  If problems arise, like greater than normal oil consumption and/or exhaust
 smoke then revert back to the conventional oil.  Be sure to change the oil
 filter when you change the oil.

This can be a bit on the spendy side, especially the constant changing of oil 
filters, but it's better to spend a little money on safety then spending a lot 
of money on an engine rebuild!
     Toby Erkson, air_cooled_nut@pobox.com
     '72 VW Squareback 1.6L bored and stroked to 2.0L
     '75 Porsche 914 1.8L
     Portland, Oregon, http://www.geocities.com/MotorCity/8501/
P.S. I've spent over an hour on this problem, editing and revising -- it's not 
something that I just whipped out -- so there was thought put into it.

______________________________ Reply Separator _________________________________
Subject: synth oil in high milers?
Author:  type-3-errors@umich.edu at SMTPGATE
Date:    11/17/97 5:32 PM

What is the going thinking on adding synthetic oil to a high mileage motor
for the first time?  Compression is within tolerable limits...It's my 
girlfriends '79 Mustang V6 (yech)...