FW: pentosin substitutes revisited - verrrrrry interesting stuff

[Livolsi, Stephane]

> I think it is more like this... Audi specifies a mineral oil for use in
> a system.  They give it a number, in this case G002000 (aka "goo 2k"),
> and obtain it OEM for their own branded containers to supply to dealers
> (I have a can of Audi power steering or brake fluid around here
> somewhere...).  At some point, the OEM mfr, and even others who get the
> spec (ie, Pentosin, Febi, etc.), make their own product and stamp the
> compatible manufacturer codes on the can along with their own
> nomenclature.  Hence the can of something-or-other up at Atlantic I saw
> with a brand name, a brand name product name (ie 7S or 11S etc.), and 3
> or 4 manufacturer applications on the side (ie Audi/VW G002000, BMW
> this, Benz that... and the other thing)
>
Right, except that Audi doesn't make the hydraulic systems in our car.  They
have someone else (ZF for example) make them and so it is the manufacturer
of the hydraulic system parts who specifies the requirements, not the
manufacturer of the car.  But like you say, then the car manufacturer names
it and brands it, etc.

Although I haven't seen it in black and white, indications are that the
pumps in Audis are of the vane type (as opposed to piston) and the ZF
specification for the fluid used in these pumps is TE-ML 09.  I did a web
search for "ZF TE-ML 09" and got a couple of hundred hits with 99% of them
being in Europe and Asia but still I could see the words Mobil, Shell, and
others and could deduce that these companies have TE-ML 09 equivalents BUT
none of their North American websites list an equivalent.  So I cross
referenced other lubricants that were listed under the same applications as
TE-ML 09 and found that Dexron and Mercon ATF's can be used in the same
applications.

This was a pretty neat search and I learned a lot about hydraulics and
viscosity.

The bottom line?  The Audi hydraulic systems need a mineral or synthetic
based fluid (as opposed to dino oil).  The Pentosin website shows the specs
for ch7 and ch11.  Virtually any mineral or synthetic hydraulic oil should
work well in our systems if the hot and cold viscosity specs are close to
ch7 and ch11.  The biggest disparity that I found was in the viscosity index
which I understand better now (thanks Stephen Kormilo).  It looks like there
are lots of hydraulic fluids out there that will work at moderate and
operating temps, but it's the cold weather performance that may prevent
their use in our cars.
I am still going to investigate what the loggers around here use in their
heavy equipment in winter.  It could be that they change fluid from summer
to winter, something that I don't think I want to do to my car.

Stephane