Washer fluid directions in German
 

Does anyone read German that has a liter of the WinterFit washer fluid? Directions are in German. On the label it indicates one liter of WinterFit to some part water depending on the temp. I don't know what part water they are indicating (quart or gallon). Can I mix this with my regular winter washer fluid from Wal Mart? I also have a bottle of the SummerFit - it's a small bottle and is to be added to the washer fluid.

I'm taking a winter trip in two days and want to premix some extra washer fluid but can't read the directions, esp. on the Liter of WinterFit. Need to know if I can add the WinterFit to either plain water or to my regular -20 degree fluid from Wal Mart and what the mix should be.

I am almost certain that the Wal-Mart washer fluid will do for any temparature that you might encounter. Is the washer fluid container in your 2008 Mercedes not also heated?? If the WinterFit bottle quantity is shown in liters, I would think the quantity of the water to be added is also in liters.
I will be driving through Montana/Idaho/Utah/California again next week, I don't expect to add anything but the regular washer fluid at the gas station.