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Synth winter weights (fwd) Good Read
I thought this was a great informative message. Anyone with interest may
want to read it.
1984 4000s quattro / modified/ awaiting Turbo Transplant.
1985 4000 quattro / Silver / Fixing it Up.
1987 4000cs quattro / Saphire Metallic Blue/ Girlfriend's
1996 A6q / Volcano / Dads Car
*****1985 5kt / PARTING OUT!
---------- Forwarded message ----------
Date: Tue, 6 Oct 1998 12:33:43 -0500
From: Ted Kublin <Ted.Kublin@msfc.nasa.gov>
Subject: winter weights
>In response to your question regarding the 5w-50 synthetics ....
>In order to make such a wide range, you start out with a lighweight
>basestock and add a fairly large percentage of V.I. improver to it. These
>V.I. improvers are special types of long chain polymer thickeners that
>expand (uncoil) at high temp to give the oil it's 50wt characteristics.
>However, they add no lubricating value and decrease the amount of actual
>basestock in the quart of oil that you buy. In addition these polymers
>tend to break down (the polymer chains are physically ruptured) from the
>shearing action inside the engine - this can cause deposit buildup and
>cause the oil to actually thin out over time. You are always better off
>using the narrowest viscosity range oil you can; particularly in a
>turbo-charged engine. If I lived in Idaho, I'd simply run Mobil 1, 0w-30
>or 5w-30 synthetic in the winter. I run now the Amsoil 0w-30 synthetic
>year round in both my Audi and VW in Huntsville, Alabama with no problems
>at all. I also spent four years stationed at Edwards AFB, CA (the Mohave
>Desert) and ran the 10w-30/0w-30 there also - it was common for the temps
>to stay over 100 degrees for several weeks in the august. I find that
>these 4 & 5 cylinder VW engines run noticably better with the low viscosity
>synthetics - my oil temps are 15-20 degrees cooler and performance and fuel
>efficiency is better (3%-5%). My 1990 Audi 100 (2.3 L, non-turbo), has
>145,000 hard miles on it and uses no oil between changes - this is with
>drain intervals of 10k-12k miles ....
>Unless your engine is really worn or is leaking oil there is NO need to use
>anything heavier than a 10w-30 synthetic. As for Audi's oil
>recommendations - these are based on European driving conditions and the
>use of petroleum oils; this necessitates the use of 15w-40 or 20w-50 oils
>to provide adequate oil pressure at very high (230-260) oil temps. I have a
>hard time getting my oil temps over 210 degrees F - even in the middle of
>the summer. I've tried using the Amsoil 20w-50 synthetic in the summer and
>the car runs much hotter. Finally, I've been doing periodic oil analysis
>for the past 6 years and the wear rates with the low viscosity synthetics
>are comparable to the 20w-50 synthetic racing oil ...
>ps: feel free to post, as this is a common misconception on the list that
>you must use these heavier oils in German cars ....