Guys,
my car was running fine until few days ago. 80-82 degrees during city driving.
Now it was almost touching 100+

I added coolant and washer fluid bought from autozone.

Do you guys think this is the problem?
If so what coolant should i use.

Can i just add MB coolant or should i flush old one out and add MB one??

Really need help with this. Thanks in advance.

Note: Radiator was replaced in Jan-08 and found no oil or water leaks underneath car.

__________________
1) '04 S500 Gold/Beige......120k Miles
2) '93 300E 2.8...Green/Tan MBTex..........202k Miles(and going)
3) '89 420SEL...Light Blue/gray Leather....155k Miles (Retired )

That's not necessarily a problem. Did you switch the climate system from a/c to economy recently? With the a/c switched on the electric cooling fans will run on low speed much of the time, keeping the coolant temperature at ~85. On economy the fans don't run until the coolant reaches 105, then they switch on high speed.

It's quite possible your engine driven viscous fan clutch is bad; it should engage as the coolant temperature rises and draw additional air through the radiator.

- JimY