Coolant Question

[coreseller]

A friend of mine who lives out of town had an issue with his Boxster S recently. While out and about his car decided to let loose of some coolant via the cap dumping it onto the ground in front of the passenger side rear tire.

I'm aware of the coolant cap issues and that several revisions to the original design have come forth, that part of the solution has been identified and the updated part is on order. He also pulled back some of the interior carpet around the reservoir and checked it for moisture / leaking, all dry.

After a brief phone conversation he found some water (not sure if it was distilled) and added about 2/3 of a gallon to the cooling system, wiped down inside of the cap threads, secured it and drove the car home for about 45 minutes without any issues or spiking temps.

Question; would adding that amount of water to the coolant have an adverse effect on anything? He lives up north so would the effective freeze rating of the Porsche coolant be drastically changed? Lastly, is the OEM Coolant only available through dealerships?

Thanks Guys.......Mark.