"I used tap water (before I did any work on engines) in my wagon for the last few years and I noticed rust had accumulated when I rebuilt the head. I would not advice tap water for long term usage."


How are you correlating rust to using pottable water? I think Mercedes and the engineers and chemists have more knowledge on the subject than us. I TRUST them and talking with long term Mercedes shop (Stu Ritter) whom has a BS in Chemistry- you want to use tap water. If you have extreme water in your area- just buy a gallon jug a the store. Stu worked on the everyday for 30 years never saw problems with regularly changed coolant.

M