Okay, here goes...
Every other day (or so) when I start my car in the morning the power steering will groan (usually for about the first five minutes of driving). It is louder when turning left than right, though I'm not sure if that means anything. The fluid and filter were changed about five months ago, so that cannot be the problem. This started about 3 weeks ago, and nothing has happened around that area to cause this, that I can thnk of. I checked the fluid level, and I cannot see a mark of where it should be. The fluid is about half way to the top of the reservoir. Is this the correct level? And if so, what could be causing this noise? Thanks for any help!
Justin
(oh, sorry...it's a 1987 560SEL)

Sounds like air in the pump. With the steering centered, remove the cover from the resevoir and see if there are any bubbles. If so, your level might be a tad low and the pump is entraining air, whic can be very noisy and distressing.

I would think its trapped air when you had the fluid changed.

I don't think the fluid change could be related since it was five months ago, the noise only started last month...

the last time mine ball joint was shot, the car groan too when steering. u can check this easily. it started out as intermittent and get progressively worse..

its quite troublesome to change it, u have to take the front suspension apart to press the old joint out. I removed the lower arm so that i can press it out properly and i replaced the bushing as well.

It's definitely the power steering causing the noise. If I am at a stop and I turn the wheel it will make noise, so the ball joint can't be the problem...

I do not think so...
mine groan also when the car is stationary

the ball joint will rotate together with the wheels when they turn, it doesn't matter whether the car is stationary or not.

but of course, I am not saying yours is definitely the ball joints, just a possibility.

regards
brian