Check for good heating and defrost systems
Marks says you should check the heater, battery, radiator, and front and rear defrosters for signs of aging or lackluster performance. These are among the most important pieces of equipment on a beater. They're also among the most vulnerable components to cold-weather failure.
As a test, Visnic suggests getting in the car for a few minutes and shutting the doors. When your breath begins to steam up the windows, start the car and turn on the defroster, with the fan setting on medium-high and the temperature control at its highest.
"Unless it's chillingly cold outside, a properly working defroster should begin to defog the windshield in just a few minutes, essentially as soon as the engine begins making a little excess heat," he says. The side windows should follow fairly quickly.
Also be mindful of suspicious smells.
"If you have the heat blasting and detect a sweetish, burning smell inside the vehicle, something in the cooling system isn't working properly or there's a leak," Visnic says.