Accelerate the engine quickly a few times. A whining noise can indicate worn or slipping belts. Leave the car idling while you get out and look at the exhaust. If there is blue smoke, it may be burning oil. Black smoke may be unburned fuel.
Excessive steam can be a sign that coolant is leaking.
There could be a leak in the exhaust system. It is a necessity in New England, but if you are buying a car in the summer, you may not discover that you have a problem until the winter. If the car has air conditioning, try it, even if it is January. Test all systems including power windows, electric seats and alarms. Do not wait until your warranty has expired to find out that something does not work.