2.13 – Driving in Winter 2.13.1 – Vehicle Checks Make sure your vehicle is ready before driving in winter weather. You should make a regular Vehicle inspection, paying extra attention to the following items. Coolant Level and Antifreeze Amount. Make sure the cooling system is full and there is enough antifreeze in the system to protect against freezing. This can be checked with a special coolant tester. Defrosting and Heating Equipment. Make sure the defrosters work. They are needed for safe driving. Make sure the heater is working, and that you know how to operate it. If you use other heaters and expect to need them (e.g., mirror heaters, battery box heaters, fuel tank heaters, check their operation.