My car is at around 82k miles. I replaced the alternator a few weeks ago (before realizing that it was a recall issue) and a week after I'm in traffic and I see steam coming from my hood and my temp gauge a little higher than normal. I drove it back home because I was only 5 minutes away. Right as I pulled into my driveway the temp started soaring and I had to coast it the rest of the way to avoid damage. I let it cool down and started it back up just fine. I opened the hood so I could see where the leak was coming from. I saw nothing until it hit operating temperature and that is when I saw steam coming out right under the throttle body. I am fairly certain it is the water pump. But from what I have read, when these fail there is typically an impellar noise that you can hear and it leaks coolant, not steam.