This morning when I turned the steering wheel, I heard a grinding noise. So, I opened the cap to the power steering fluid, it was practically empty.

I'm going to the dealer to buy some fluid tommorrow, can I just fill it to proper level, or do I have to drain or pump out the old fluid. I'm asking this because this is 98 E320 and I want to make sure that it's ok to the mix the new fluid with what is left of the old fluid?

usaims

 

they just don't drop all the fluid. It went someplace so you can't just fill you need to diagnose the leak and repair the seal or gasket or replace the unit or hose etc. if you just fill you are running the risk of lost P.S. when you most need it.
When you have it repaired then you bleed it to remove all the old fluid and get the air out.
Find an indie if you don't diy. Do not take this one to the dealer
For warned is for armed.

1.1 us quart

 

You'll probably want Mercedes brand fluid. Or, grab some cheap stuff, pour a little in, and see where it leaks. Fix that, then use Mercedes fluid.