RE: Pentosin 11s vs 7.1

[James Desveaux <desveaux@ucla.edu>]

Dan:

I went through the same process of trying to figure out which will work.
Here's what I learned.

1. Contrary to what some say, either 11s or 7.1 will work, and neither will
eat away at your seals.

2. Most dealers now carry 11s exclusively.

3. The viscosity of 11s is slightly higher than 7.1.  From 1989 on, Audi
changed a couple of things on the racks on the larger (type 44) cars.
YOu'll notice (if you look closely) that early 89 and earlier type 44 cars
have smaller diameter steel pressure feed lines on the racks (the steel
lines that look like brake lines that run parallel on top of the rack).
The mid 89 and later type 44s have much thicker (larger diameter) steel
lines.  Jorgen folks told me that because of the changes in the diameter of
those lines, and changes in the hydraulic pumps in at least the '91 20v
cars, the system pressure is a bit lower, and the pulsation at the racks
seals is reduced, and supposedly the later racks fail less often (notice I
said supposedly).  When they made this change, they started using Pentosin
11s, since it's higher viscosity, and it supposedly works better on the
later cars.

I don't know that any of this is an issue on the smaller cars, like yours,
since rack failure was never an issue.

I have been told that if you use Pentosin 11s on the earlier cars that
still have racks with narrow ID steel lines, the cars are tougher to steer
at startup in cold weather, and that may not be good for the steering system.

My guess is that your car came with 7.1, since it's an 88.

Hope this helps.

- Jim