Hi all I have a 1991 nissan stanza that is badly overheating and theres tons of smoke/vapor coming out the exhaust. the car is operating in outside temperatures of 5 above to -15 below zero. I was driving from northdakota to iowa and in south dakota it just all the sudden jumped up from normal tempm to hot and a bunch of what I think was water vapor came pouring out the back. I looked underneath the car and saw some fluid but couldnt tell where it came from. I went through about 3 gallons of antifreeze in about 15 miles. Hope this helps. Dutch

A couple of things to check:
1. Your cooling fans working.
2. Is your thermostat stuck.
3. Does your rad leak are youe hoses secure.
4. Is your water pump working properly