[Vwdiesel] Oil Debates

[Val Christian]

I'll chime in again.  I've lost count of how many diesel VWs I've owned, and 
how many millions of miles I and family members have put on them.  

My currently owned 91 NA has 200K, and compression tests at 495 +/-5 on
each cylinder.  I bought the car new, and broke the engine in myself
(another thread on how to break in engines).  The cylinder head gasket
failed, and was replaced about 5K miles ago.  At the time, the hone marks 
were visible on all parts of all the cylinders, and the ridge was less 
than 0.001.  I did not touch the rings, nor did I pull the pistons.
I did replace the valve seals, and the exhaust guides, which were starting 
to reach wear limits.  This car's oil history up until about 150K miles
was Cast. 20W-50 (the old CD rated formula), and straight weight 30 or 
40 oil.  The change interval is 2500 miles.  Sometimes it gets to 3500
miles.  I change the filter about every 5000 or even 10000 miles depending
upon conditions.  (The filter change is mostly because I am lazy and 
on this car the filter only comes out one way, and always makes a 
mess and requires pulling the lower shroud, and moving power steering lines,
etc.)  I can't tell you exactly how much the engine burns, because it 
leaks far more than it burns.  I don't have to add oil between changes.

I have recently avoided 20W50 oils, because examination of my experience 
on the many VWdiesels I've run suggests that the heavy oils tend to aggrivate
sticky rings, especially on some of the cars with very high mileage, and 
other problems.  Specifically, on one 79, with over 550K, and 500K since
rering, I found that I had high blowby, hard starting, etc.  I switched
to a lighter weight, high detergent oil, and the sticky rings and blowby
problems went away.  Later I resumed the heavy weight multivis oils, and 
the problems came back.  To the point of recent discussion, would a 
synthetic oil help?  It would probably help reduce the stuck rings.  
However, the $0.99 Mobil oil I used at the time did the same thing, and
at lower cost.

On the 03 TDI that I currently run, which has 80K miles, I use Rotella
5W40.  When I got the car, Walmart was selling the oil locally at prices 
between $9.xx and $12.84/gal.  I bought about 20 gallons, figuring that
was a good price, and that I had a short lifetime supply.  My recall 
is that this is not a "full" synthetic, and also that it does not meet 
the warranty requirement for VW.  I change every 10K miles, except 
that I have done a couple of 5K mile changes situationally based upon
operating conditions.  Thusfar, I have replaced the filter with a VW filter
every change.  I inspect the old filters for metal glint, which is easy.
The engine is too young to even consider a compression check.  It consumes
about 1/3 quart every 10k miles.  Since it has a turbo on it, I don't
plan on running cheaper dino oils.  Are there better oils than I use?
Absolutely.  And there are certainly much better filters.