synthetic oil consumption

[Carl DeSousa <desousa@cisco.com>]

> From: Jeff_Skelley-C13386@email.mot.com
> 
> <I recently read from the list that someone had stated that there is more blow-
> <by at cold start with the synthetics than with regular oil.  
> 
> Nonsense.  Let's not forget why synthetic oil was created.  The Germans came 

"Nonsense"?  Let me try explain some "sense" it to this.
(since I  made that statement originally)

Lets not forget that synthetics work differently
than fossil oils either.  Synthetics get in to places that fossil oils
do not.  Maybe some engines weren't designed and toleranced to 
use synthetics, *especially* after many miles of service and wear?
Try running it on a 911,  ta dah... now all of a sudden oil leaks
develop, and consumption increases.   So guess what, when cold,
tolerances are at thier "loosest", therefore more oil gets through.  
Its not rocket science.  This probably occurs less when warmed cause 
everthing has expanded, tolerances have "tightened".
I have tons of data in my Bosch handbook about oils too.  Yes
synthethics have superior lubricating properties but is it possible
that they have inferior "sealing" properties?  As the Church lady
would say, hmmm? hmmm? :)
 
> upwith synthetic oil in WWII to keep their engines running in the N. African heat 
> and Russian Winter.  The synthetic oil did very well in both conditions.  I'm 
> not trying to say that regular oil additives have not changed in 40+ years but 
> mearly synthetics were designed for extreme conditions.

Right, but that has nothing to do with blow-by and why many engines
consume more synthetic oil than fossil oil.  

> 
> <Does this give better "cold start" protection?
> Synthetics flow better in cold conditions, see additional post below.

Yes, synthetics provide better protection during cold starts since
amongst other things, they remain more "fluid" when cold.  

Carl DeSousa
Mechanical Engineer
Cisco Systems