The shifts in temperature and moisture that accompany changing seasons can take a toll on your car—and on its performance. Have the following services performed at least twice each year.
Check your antifreeze/coolant level. The most common cause of engine-related breakdowns is cooling system failure. If you top off the coolant yourself, check the label on the coolant bottle to ensure it's the recommended type for your car make and model. Use a 50:50 ratio of antifreeze to water.
Replace your windshield wiper blades every year. In extremely cold climates, fill the washer reservoir with freeze-resistant wiper fluid (water and standard windshield washer fluid will freeze) and keep an extra gallon in the trunk.
Check your battery. If it is more than three years old, have a service technician test its capacity and the output of your alternator. Make sure the battery terminal ends are corrosion-free.
Check your tire pressure before you've driven more than fifteen minutes. This ensures that the tires are inflated to the proper pressure (listed on the sidewall). In colder weather, the air inside the tires will contract, and the pressure will drop.
Check the tread depth on your tires. Hold a penny between the treads. If you can see the top of Lincoln's hair, it's time to replace the tire. In areas with a lot of rain, you should use the same "hair" rule with a nickel instead of a penny. In snowy/icy climates, consider changing your regular tires to winter/studded tires for the season.
Heat/Cooling System and Lights
Check that your lights, heater, and defrosters are working properly. Before summer, have the AC system checked and recharged if it's not doing a good job cooling incoming air.
Hoses and Belts
Check all rubber hoses and belts to ensure they are not damaged. Coolant hoses wear from the inside out. Inspect for heavy cracks or chunks missing from the belts.
If you haven't had it inspected in the previous six months, have your car's brake system checked.
Winter Emergency Kit
Assemble a winter emergency kit and keep it in the trunk of your vehicle. The kit should include a blanket, extra boots and gloves, an ice scraper, windshield washer fluid, jumper cables, a first-aid kit, flares, a small snow shovel, a flashlight, kitty litter (for traction when stuck in the snow), and bottled water. Bottled water is good to keep in the car regardless of the season—you want to stay properly hydrated if you have to wait for help by the side of the road.
"Winter Weight" Oil
In very cold climates, consider changing to a "winter weight" motor oil, which works better in lower temperatures (regular oil grades get too viscous at low temperatures). 5w-30 is a typical winter-weight motor oil.
Keep the gas tank 1/2 filled all winter long. This reduces the likelihood of moisture buildup in the fuel lines. Moisture buildup increases the likelihood that fuel lines will freeze and fail.