Check Coolant Level Malfunction

I have 2001 W210 E-430. I look under the hood and found no coolant sign splash all over the engine, this tells me that radiator is fine and there was no major spil or lekage of coolant in engine compartment, but I did see some water like liquid on the cover that goes under the front grill/Radiator.
I check on my garage floor and did not see any sign of liquid on floor also.
I drove the car yesterday and did not see any temperature rise, temperature looks normal, staying around 80.
I have following question.
1. Is there is any spcial coolant that I need to put into the car, I mean MB Part number 210 XXX XX XX or I can buy any standard coolant and fill it up.
2. At what mileage Radiator take dump, I got 76000 miles on my car.
Any response and help will be appreciated.



