[rdancd816]

I think you should be fine. My '97 is a Dallas car and I've had it up to Leadville, CO which is over 10,000'. No issues with the tank. Don't know what year your car is but I would be sure to have the updated coolant cap (if it's a 986) to prevent any chance of an overflow. This would not rupture the resevoir but could spill a lot of coolant. Have a great trip!