Hi,
new to the group, and a first time Nova owner. Just had a 1970 non- SS Nova brought up from California to Canada. After about 15 min of driving, the windsheild begins to fog at the bottom. Heater is off. Heater works fine when on. Any suggestions?

Thank you,
ST

Welcome to the site.

Could your heater core have a really small pin hole that is allowing a fine vapor out!

No telling what's gone on over the lifetime of your car. Are you breathing hard when behind the wheel? ;) just kidding, but in winter having a talkative person in the car can fog the windows. A leaking heater core sure could cause the problem as already suggested. I have seen many reasons for this in old cars and new. A window being left open during a rain comes to mind as does a leaking windshield. Once water permeates a cars interior you really have to work at drying it properly. Parking the car in the sun with windows down on hot dry days really helps. Not parking the car in a dark dank musty garage will help too. Leaving the lever on defrost and letting fresh air circulate is good too unless you are in a real humid wet climate.

Look for signs of rust in the cowl area and under the dash, it will help you isolate the source of moisture.

Sounds like heater core...if your face breaks out with sores or rash then a mist of radiator fluid is getting in via heater core hole or bad heater core hose connection.