power steering fluid

[HOOKSA <HOOKSA@aol.com>]

I was wondering if anyone knows if the mineral oil in the power steering
systems for the 90's, A4's, ect.... changes color after time.  I was worried
some grease monkey made a mistake, but talking with a dealer today, he said
the clear mineral oil turns dark over time.  Is this true or should I have
then change it, when it goes in for warranty things this week?  Also now that
summer is starting and I use my A/c on my 96 A4, I hear more belt wine/hum,
not squeal.  Is this normal/ do others have this noise.