I've been using water for a while now and the car runs fine after I empty the radiator down and pour fresh water into it. I took it to three places and nobody knows what it is. I have a gasket leak but it wasnt a severe problem at first. The guy told me to just keep coolant in the car and everything was fine and it worked until now. The car also makes a weird noise after a while sounds like a burp coming from the bottom of the car somewhere.