Steering whir

Occasionally when I'm driving my 98 SL2 slowly (in the parking lot, for
example), I hear a distinct whir/hum from beneath the hood when I'm
turning the car, presumably the power steering in action. Since I didn't
used to hear/notice it, I'm a little concerned. Any reassurances or
cautions?

 

Probably the alternator, should get it checked.

 

How's the fluid level on the pump's reservoir?

 

This is not uncommon. The PS pump really has to work when you turn
the wheels at low speed. Most cars will make this sound.

If it turns into a squeel or seems to be more or a chatter, then you
might get it looked at.

Wouldn't hurt to check the PS fluid level, though, as Jonnie says.