hello everyone. I need a lil help from u bimmer pros. i have a 92 325is. when my bmw is running for a while it starts to fog up the windows and steem comes out the vents. i have replaced the radiator and the thermostat just last month so the only thing i think it could be is the heater core. if it is the heater core where can i get one from. i seem not to be able to find one where i live or online and i dont want to buy it from the dealer. any suggestions will be greatly appriciated.