Re: Pentosin Woes

[Phil Rose <pjrose@servtech.com>]

>Date: Fri, 13 Nov 1998 05:23:43 -0500
>From: Robert Myers <rmyers@inetone.net>
>Subject: Re: Pentosin Woes
>
>At 08:17 AM 11/13/98 GMT, you wrote:
>>In message <364B9B4B.4070@earthlink.net> Wolff writes:
>>
>>> Does it then follow that 11S can be used on top of 7.1?
>>
>>That's the conclusion I came to from the service microfiche.
>>
>
>This is kinda like the idea that it is OK to add a quart of Mobil1 to your
>crankcase full of Valvoline.  They both do the same job and are fully
>compatible.  The 11S *may* be a bit better.  Then again...  Overkill?
>

Well, maybe it's a comparable situation for small additions, but after
complete changes to synth motor oil, some have had seal leakage on high-ish
mileage engines. Doesn't always happen, I guess, but my understanding is
that the synth oils tend to de-swell old rubber seals somewhat (or at least
I'm told they _used_ to do that). In the case of switching to Pentosin 11S
hydraulic fluid, the de-swelling of old seals presumably doesn't occur (or
isn't serious enough to cause leakage).

However, if a seal problem is avoided by reason of the fact that 11S
actually causes _more_ swelling (than does 7.1), then there could be a
leakage problem after an 11S system is changed over to 7.1. This concern
may be entirely unwarranted and is purely my speculation. But without some
info from Audi, I wouldn't assume that Pentosin 7.1 is a suitable
substitute for 11S, except maybe for small additions in an emergency
situation.


Phil Rose				Rochester, NY
'89 100 (For Sale, 111K, automatic)
'91 200q				mailto:pjrose@servtech.com