My wife was driving the 300e last week when I was out of town. The low coolant light came on. She had the smarts to add antifreeze, but she did not know there was any difference between the MB coolant and Prestone.

She added about 1" of Prestone to the reservoir.

Will this mess up the the coolant? Should I drain it and replace with MB coolant, or not worry about it?

Bill