YOu can put pretty much anything in the radiator to hold you over til you get to the dealer.
Once I got stuck with a big leak in my radiator in the middle of winter, up in the mountains..... nearest service station 50+miles.
It took a few gallons of water and a magnum of vodka (to keep the water from freezing) but I made it to the service station! LOL!
With that said, try the water first..... consider it a great opportunity to flush your system.