Re: Pentosin, Oh Pentosin! (long)

["Fred Munro" <munrof@isys.ca>]

Phil;

    Your '91 200q should be filled with the synthetic oil.

Fred Munro
'91 200q  262k km
-----Original Message-----
From: Phil Rose <pjrose@servtech.com>
To: quattro@coimbra.ans.net <quattro@coimbra.ans.net>
Date: Tuesday, November 10, 1998 7:06 PM
Subject: Pentosin, Oh Pentosin! (long)


>I sure would like to better understand the Pentosin "issue". I have no
>intention of using ATF, but what about Pentosin 7.1 vs 11S??? I suppose
>it's old hat to most of you, so I'm sorry for the WOB in retracing the
>trail of green tears.
>
>My '91 200q bears the inevitable label ("use G002 000 mineral oil only") on
>the reservoir. It contains hydraulic fluid that appears only very _faintly_
>yellowish when viewed in a pipette tube (OK maybe a slight greenish tinge,
>if a lot of imagination is used). That's also the color my local Audi parts
>guy describes for the sanctified G002 000 fluid they presently dispense. Is
>this different than the color of "green" Pentosin 7.1??? I suppose it's
>possible that when a much thicker (larger) layer of my car's PS fluid is
>viewed, it may merit the unequivocal "green" designation that people on the
>qlist apply to Pentosin 7.1. But....anyway, I wonder which fluid  was put
>in my car at the factory in late 1990? And what type of fluid was added to
>it at later dates?
>
>Results of several recent phone calls---->
>
>(1) AoA Customer Service claims there is only one fluid p/n ever specified
>for use in Audi PS pumps, and they conveniently identify that only as G002
>000. My understanding is that at one time, G002 000 actually meant
>"Pentosin 7.1".
>
>(2) Customer Service claims to have no info available on G002 000
>composition (or when it may have changed), but I got the dealer parts dept.
>guy to read the label on a can of their G002 000, and the following words
>of comfort appear:
>
> "contains Pentosin 11S" !!!!
>
>[Not to confuse the issue, but Audi also use a p/n G002 012 fluid, which
>they claim is merely a 12 oz quantity of the same G002 000.]
>
>So, as we all knew, Audi at some time in the not-so-distant past changed
>their hydr. fluid from Pentosin 7.1 (mineral oil) to Pentosin 11S (a
>synthetic blend containing mineral oil), but they retained the same p/n.
>But starting with what model year? And should anyone care? Some say "Yes!",
>while others think it probably matters not at all.
>
>Not matter? But, but, but there's that ominous warning on our non-OEM
>Pentosin 11S labels that it "must *not* be mixed with mineral oil or any
>other hydraulic fluids". Right? Yet it is clear that Audi is doing exactly
>that--considering all the older Pentosin 7.1-containing cars that they
>service. Therefore, either Audi is inflicting significant harm to
>customers' hydraulic systems (class action suit?), or in fact, there's
>really *no harm* done by mixing the two flavors of Pentosin. I'd like to
>believe the latter is true, although the high frequency of PS seal leakage
>raises the suspicion that admixture of 11S and 7.1 fluids might indeed be
>unhealthy. Bet you won't get Audi to admit that...:(
>
>Assuming Audi is not criminally negligent, it must be that Pentosin 11S is
>indeed  _backward_ compatible with 7.1 (i.e., that it's OK to replace 7.1
>by 11S). But what about that warning, you ask? Well, I don't know. Possibly
>it just doesn't apply to Audi components, or it might indicate that the
>reverse, i.e., replacing 11S by 7.1, is not advisable. Thus, if 11S tended
>to swell rubber seals, then it might not cause seal problems (leakage) when
>added to a Pentosin 7.1 system--if the latter is a relatively non-swelling
>fluid. But if admixture occured in the opposite sense (7.1 added to an
>established 11S system) some _de_swelling of seals might start to occur and
>eventually...leakage. Pardon the hand-waving, but it's all I can think of
>at the moment. Whether this reasoning would be applicable to steering rack
>issues, I don't have a clue.
>
>Based on my present level of ignorance, when I rebuild my PS pump (if
>Carlsen ever gets the kit shipped to me :( ) I'm probably going to flush
>and refill with Pentosin 11S. And keep my fingers crossed...
>
>Phil R.
>
>P.S. If anyone wonders, there's a simple explanation as to why swollen
>seals will often begin to leak after they've been de-swollen--even though
>the same seals can seal OK if never swollen to begin with. A similar
>phenomenon occurs in woodworking joints, too.
>
>
>
>
>Phil Rose Rochester, NY
>'89 100 (For Sale, 111K, automatic)
>'91 200q mailto:pjrose@servtech.com
>
>
>