FW: pentosin substitutes revisited - verrrrrry interesting stuff

[Stephen Kormilo]

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At 09:50 PM 30/09/02 -0400, you wrote:

>From: "Livolsi, Stephane" <Stephane.Livolsi at investorsgroup.com>
>To: Audi Quattro List <quattro at audifans.com>
>Subject: FW: pentosin substitutes revisited - verrrrrry interesting stuff
>Date: Mon, 30 Sep 2002 18:51:37 -0500
>
>
> >     As far as your ZF info goes, they are saying that if you have central
> > hydraulics (e.g. brake assist/self levelling) then you need to be using
> > G002/Pentosin/whatever they call it round your way.
> >
>Actually, I was trying to point out that ZF does NOT specify G002/Pentosin
>which I found very curious.  I suspect that Audi chose Pentosin as a
>supplier and therefore specifies only G002 as acceptable, even though there
>may be other hydraulic oils out there that are safe to use in Audi systems.

snip.....

>What I found was that many of them are very close to the pentosin specs
>EXCEPT in 2 categories - Viscosity Index and 'Viscosity at -40C'.  The
>viscosity index for 7.1 and 11S is 340 and 320 respectively.  ALL of the
>other oils that I found that spec'd similar to pentosin had much lower
>numbers including Mobil DTE 13M.  The DTE comes in at 140.  Let me be
>honest, I DON'T KNOW WHAT THIS MEANS.  For all I know a lower number may be
>better.  Does anyone know?

A lower viscosity index means the oil is 'thinner'.  This is probably 'bad'
at higher temperatures.

>Also, the viscosity for DTE (as an example) at -40 C is 5110 whereas for
>pentosin it is listed at <1100.  Again, I don't know if this is good or bad.

At cold temperatures, a higher VI is 'bad' because the oil will not flow as
readily, just like regular motor oils, e.g. 5W-30, the 5W is the VI for
cold (Winter) temperatures and the 30 is the VI at, or near, the normal
operating temperature, IIRC.

>The flash point for 'other' oils tends to be 20-40 degrees C above pentosin.
>This I suspect is good.

Agree.

>Let's face it, if you have a good hydraulic system, the cost of pentosin
>shouldn't be an issue because you use so little of it (provided your system
>doesn't have the 'seive' option).  My reason for looking into this is
>availability (try asking for pentosin around here if you want people to look
>at you like you have 2 heads) and also potentially cheaper hydraulic system
>flushes.
>
>Just some food for thought
>
>Stephane

Stephen Kormilo                     Silver 2002 Audi A4 3.0QM
                      Now departed:   Silver '98.5 Audi A4 2.8QM
                                               Black '85 Mazda Rx7 GSL-SE
Instructor, Electronics Technology
Red River College
Winnipeg, MB
CANADA

email: skormilo at rrc.mb.ca
OR
           stephen at kormilo.ca


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