Its not desirable to mix coolant types. The dealer probably just added green to bring the level up to the right amount of what was already in the car. Their computer probably has only a line item for MB coolant.

engatwork,

Distilled water is highly "corossive" and should ONLY be used with coolant. NEVER put just distilled water - it will cause rust faster than anything. MB service docs says clean drinking water is fine. I have a PUR filter on my kitchen faucet and that's what goes in the car for water.

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Brian Toscano