99 ML 320 power steering fluid
 

I want to replace the fluid, should I use mineral oil based or synthetic MB power steering fluid? I want to keep the truck long term.

Either Dexron 2 ATF or MB P/S fluid is approved.

Many power steering fluid leaks on all of the ML's.

Even extended warranties on them.

Any MINERAL based fluid, whether natural or a synthetic equivalent, will work.
So will the so-called "green fluids" used in Audi, they are knock-offs of LHM.

You can also use Hyken Glacial Blue, which is made by Kendall, I believe, it's about 8.00 a gallon, so it's cheap if you leak a lot.

I have a 99 ML 320 with about 275,000 miles on it. I have been using the Mercedes fluid. It leaks pretty badly these days. Have to top it off about every two to three weeks. If I get one of the cheaper fluids mentioned above, can I add it on top of the Mercedes fluid, or would I have to remove the existing fluid first? If I have to remove it, can I just suck it out with my Mityvac or do I need to drain it more thoroughly?

Also, what is the proper way to check the fluid level? I know the engine needs to be running, but do you 1) insert the dip stick until the bottom of the cap touches the reservoir or 2) do you screw the cap all the way dow? The graduation marks on the dip stick are spaced pretty closely and this makes a significant difference.

So, what is the best way to check the p/s fluid, and mineral based is the way to go? I think I am leaking P/S fluid and I want to top it off first and see if I can find the leak from there.