RE: 1991 Audi 100 PS fluid

[Dave Conner <conner@cfm.ohio-state.edu>]

This was discussed between June 15-21or thereabouts.

A summary of what I learned:

Audi changed the fluid from mineral to synthetic around 1990, but kept the
same part number (G002 000)

Synthetic and mineral are BOTH GREEN and they should not be mixed according
the the label on the can.

The Audi fluid comes in a can with Audi logos all over it.

Pentosin is an aftermarket product.  Their mineral fluid is called CHF 7.1,
the synthetic is CHF 11S.
Both fluids are green.  7.1 comes in a can with a green cap, 11S comes in a
can with a RED CAP.

It may be impossible to know whether the same correct fluid has always been
used in your car.  Audi has not helped things by keeping the same part
number for both fluids.  I don't know what real harm (if any) would be done
if 7.1 and 11S were mixed in the system.  

HTH,
Dave Conner