Antifreeze resorvoir needs fluid ... W124

[yosshimura]

Its down about 2 inches or so. The radiator warning light was flickering on/off last night, that's how I realized it...

Assuming there are no other problems (car was operating very well within its normal range, so don't foresse any problems), Where could this fluid have gone , how? Or is could there be something definitly wrong ?

Also, being so little,do I just pour in distilled water or mix a small batch of antifreeze / water ?

thanks