[AltimaOwner123]

Hi,
This morning (a cold morning, but not the coldest this winter) I turned on the cars heater, and after a short while, I noticed steam coming from under the hood near my windshield. (Outside the car). There was also an engine smell coming through the vents. I turned off the heater and continued driving. The steam stopped. The smell went away. Everything seemed fine. I kept an eye on the temperature gage. It never moved from mid way between cold and hot. (it's normal position). When I got to work, I again turned on the heater to see what would happen, and the steam and smell came back immediately.
Any thoughts? (1999 Nissan Altima)

[CaptainRich]

Sounds like the coolant is leaking somewhere between the engine and the heater core.
Have you lost any coolant? Check the coolant reservoir and look under the car as well.