[s-cars] oil consumption

[Mtgadbois at aol.com]

FWIW, I was told that the reason for the 0W-xx is that the newer engines  
with variable valve timing need the thinner oil to make the rapid valve train  
changes that are necessary with that technology.  Cars having that  technology 
are the 911 and the Boxster.  Since our cars do not have that  technology (but 
do when the timing belt breaks) we do not  need the thin oil.  Personally, 
2005 marks the 30th year I have used  Mobil synthetic lubricants.  Before Mobil 1 
was Delvac 1, a synthetic oil  for diesel trucks.  For me viscosity has not 
seemed to matter.  I have  used them all.  My last change was to 0W-40 and in 
about 2000 miles I'll  probably change back to 10W-30.  
 
Mark near Chicago
 
 
 
 
In a message dated 2/9/2005 10:23:44 A.M. Central Standard Time,  
s-car-list-request at audifans.com writes:


Date: Tue, 8 Feb 2005 23:29:47 -0600
From: "Paul  Gailus"  <gailus at mindspring.com>
Subject: Re: [s-cars] oil consumption
To:  <s-car-list at audifans.com>
Message-ID:  <005801c50e68$5f7f67e0$0201a8c0 at com>
Content-Type: text/plain;   charset="iso-8859-1"

I'm sure that there are a lot of factors  affecting oil consumption,
but a higher viscosity will tend to leave  thicker oil films behind on
the cylinder walls, therefore causing more  consumption.
And zero oil consumption is not necessarily a good thing,  because
it could imply that very little oil is getting to the first  compression
ring.

I've also heard that oils with relatively low  viscosity at room
temperature could make an engine more susceptible to  corrosion
if it hasn't been started for a week or more. Not surprisingly,  this
is because a thinner oil will eventually drain off and not stick  to
parts like a thicker oil will. This has been observed with  aircraft
piston engines, where some claim that the old straight grades are  the
best for engines that aren't run everyday. So the 0W-xx grades  may
not be the optimum choice for a car you don't run very often,  especially
during the warmer season.

Paul


----- Original  Message -----
From: <stefan13 at att.net>
To:  <s-car-list at audifans.com>
Sent: Tuesday, February 08, 2005 11:16  AM
Subject: [s-cars] oil consumption


> During the recent  timing belt install, my mechanic changed the oil and put
Pentosin 5w-40 in  the car.   I previously used only Mobil1 10w-40 (green
cap),  which the car consumed at a rate of about 1 qt per 3,500miles.   with
the 5w-40, the car uses absolutely no oil, nada, zilch.  Somehow,  this seems
counterinuitive, and I am wondering if this is due to the  viscosity or a
manufacturing difference.
>
> As always, thanks  for any input.
>
> Stefan
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